ThermoPhase.h

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/**
 *  @file ThermoPhase.h
 * Header file for class ThermoPhase, the base class for phases with
 * thermodynamic properties, and the text for the Module thermoprops
 * (see \ref thermoprops and class \link Cantera::ThermoPhase ThermoPhase\endlink).
 */

//  Copyright 2002 California Institute of Technology

#ifndef CT_THERMOPHASE_H
#define CT_THERMOPHASE_H

#include "Phase.h"
#include "SpeciesThermo.h"

namespace Cantera
{

/*!
 * @name CONSTANTS - Specification of the Molality convention
 */
//@{
//! Standard state uses the molar convention
const int    cAC_CONVENTION_MOLAR    = 0;
//! Standard state uses the molality convention
const int    cAC_CONVENTION_MOLALITY = 1;
//@}

/*!
 * @name CONSTANTS - Specification of the SS convention
 */
//@{
//! Standard state uses the molar convention
const int cSS_CONVENTION_TEMPERATURE = 0;
//! Standard state uses the molality convention
const int cSS_CONVENTION_VPSS = 1;
//! Standard state thermodynamics is obtained from slave %ThermoPhase objects
const int cSS_CONVENTION_SLAVE = 2;
//@}

class XML_Node;

//!   Base class for a phase with thermodynamic properties.
/*!
 * Class ThermoPhase is the base class for the family of classes
 * that represent phases of matter of any type. It defines a
 * common public interface, and implements a few methods. Most of
 * the methods, however, are declared virtual and are meant to be
 * overloaded in derived classes.  The standard way used
 * throughout Cantera to compute properties of phases of matter is
 * through pointers of type ThermoPhase* that point to objects of
 * subclasses of ThermoPhase.
 *
 * Class ThermoPhase extends class Phase by adding methods to compute
 * thermodynamic properties in addition to the ones (temperature, density,
 * composition) that class Phase provides. The distinction is that
 * the methods declared in ThermoPhase require knowing the
 * particular equation of state of the phase of interest, while
 * those of class Phase do not, since they only involve data values
 * stored within the object.
 *
 * Instances of subclasses of %ThermoPhase should be created using
 * the factory class ThermoFactory, not by calling the constructor
 * directly. This allows new classes to be used with the various
 * Cantera language interfaces.
 *
 * To implement a new equation of state, derive a class from
 * ThermoPhase and overload the virtual methods in
 * ThermoPhase. Methods that are not needed can be left
 * unimplemented, which will cause an exception to be thrown if it
 * is called.
 *
 * Relationship with the kinetics operator:
 *
 * Describe activity coefficients.
 *
 * Describe K_a, K_p, and K_c, These are three different equilibrium
 * constants.
 *
 *   K_a is the calculation of the equilibrium constant from the
 *   standard state Gibbs free energy values. It is by definition
 *   dimensionless.
 *
 *   K_p is the calculation of the equilibrium constant from the
 *   reference state gibbs free energy values. It is by definition
 *   dimensionless. The pressure dependence is handled entirely
 *   on the rhs of the equilibrium expression.
 *
 *   K_c is the equilibrium constant calculated from the
 *   activity concentrations. The dimensions depend on the number
 *   of products and reactants.
 *
 *
 * The kinetics manager requires the calculation of K_c for the
 * calculation of the reverse rate constant
 *
 *
 * @ingroup thermoprops
 * @ingroup phases
 */
class ThermoPhase : public Phase
{

public:

    //! Constructor. Note that ThermoPhase is meant to be used as
    //! a base class, so this constructor should not be called
    //! explicitly.
    ThermoPhase();

    //! Destructor. Deletes the species thermo manager.
    virtual ~ThermoPhase();

    //!Copy Constructor for the %ThermoPhase object.
    /*!
     * @param right  ThermoPhase to be copied
     */
    ThermoPhase(const ThermoPhase& right);

    //! Assignment operator
    /*!
     *  This is NOT a virtual function.
     *
     * @param right    Reference to %ThermoPhase object to be copied into the
     *                 current one.
     */
    ThermoPhase& operator=(const ThermoPhase& right);

    //! Duplication routine for objects which inherit from
    //!  ThermoPhase.
    /*!
    *  This virtual routine can be used to duplicate %ThermoPhase objects
    *  inherited from %ThermoPhase even if the application only has
    *  a pointer to %ThermoPhase to work with.
    *
    *  These routines are basically wrappers around the derived copy
    *  constructor.
    */
    virtual ThermoPhase* duplMyselfAsThermoPhase() const;

    //! @name  Information Methods
    //! @{

    //! Equation of state type flag.
    /*!
     *  The base class returns
     * zero. Subclasses should define this to return a unique
     * non-zero value. Constants defined for this purpose are
     * listed in mix_defs.h.
     */
    virtual int eosType() const {
        return 0;
    }

    /**
     * Returns the reference pressure in Pa. This function is a wrapper
     * that calls the species thermo refPressure function.
     */
    virtual doublereal refPressure() const {
        return m_spthermo->refPressure();
    }

    //! Minimum temperature for which the thermodynamic data for the species
    //! or phase are valid.
    /*!
     * If no argument is supplied, the
     * value returned will be the lowest temperature at which the
     * data for \e all species are valid. Otherwise, the value
     * will be only for species \a k. This function is a wrapper
     * that calls the species thermo minTemp function.
     *
     * @param k index of the species. Default is -1, which will return the max of the min value
     *          over all species.
     */
    virtual doublereal minTemp(size_t k = npos) const {
        return m_spthermo->minTemp(k);
    }

#ifdef H298MODIFY_CAPABILITY

    //! Report the 298 K Heat of Formation of the standard state of one species (J kmol-1)
    /*!
     *   The 298K Heat of Formation is defined as the enthalpy change to create the standard state
     *   of the species from its constituent elements in their standard states at 298 K and 1 bar.
     *
     *   @param k    species index
     *   @return     Returns the current value of the Heat of Formation at 298K and 1 bar
     */
    doublereal Hf298SS(const int k) const {
        return m_spthermo->reportOneHf298(k);
    }

    //! Modify the value of the 298 K Heat of Formation of one species in the phase (J kmol-1)
    /*!
     *   The 298K heat of formation is defined as the enthalpy change to create the standard state
     *   of the species from its constituent elements in their standard states at 298 K and 1 bar.
     *
     *   @param  k           Species k
     *   @param  Hf298New    Specify the new value of the Heat of Formation at 298K and 1 bar
     */
    virtual void modifyOneHf298SS(const size_t& k, const doublereal Hf298New) {
        m_spthermo->modifyOneHf298(k, Hf298New);
    }

#else

    //! Report the 298 K Heat of Formation of the standard state of one species (J kmol-1)
    /*!
     *   The 298K Heat of Formation is defined as the enthalpy change to create the standard state
     *   of the species from its constituent elements in their standard states at 298 K and 1 bar.
     *
     *   @param k    species index
     *   @return     Returns the current value of the Heat of Formation at 298K and 1 bar
     */
    doublereal Hf298SS(const int k) const {
        return err("Hf298SS - H298MODIFY_CAPABILITY not compiled in");
    }

    //! Modify the value of the 298 K Heat of Formation of one species in the phase (J kmol-1)
    /*!
     *   The 298K heat of formation is defined as the enthalpy change to create the standard state
     *   of the species from its constituent elements in their standard states at 298 K and 1 bar.
     *
     *   @param  k           Species k
     *   @param  Hf298New    Specify the new value of the Heat of Formation at 298K and 1 bar
     */
    virtual void modifyOneHf298SS(const int k, const doublereal Hf298New) {
        (void) err("Hf298SS - H298MODIFY_CAPABILITY not compiled in");
    }
#endif

    //! Maximum temperature for which the thermodynamic data for the species
    //! are valid.
    /*!
     * If no argument is supplied, the
     * value returned will be the highest temperature at which the
     * data for \e all species are valid. Otherwise, the value
     * will be only for species \a k. This function is a wrapper
     * that calls the species thermo maxTemp function.
     *
     * @param k index of the species. Default is -1, which will return the min of the max value
     *          over all species.
     */
    virtual doublereal maxTemp(size_t k = npos) const {
        return m_spthermo->maxTemp(k);
    }

    //! Returns the chargeNeutralityNecessity boolean
    /*!
     * Some phases must have zero net charge in order for their thermodynamics functions to be valid.
     * If this is so, then the value returned from this function is true.
     * If this is not the case, then this is false. Now, ideal gases have this parameter set to false,
     * while solution with  molality-based activity coefficients have this parameter set to true.
     */
    bool chargeNeutralityNecessary() const {
        return m_chargeNeutralityNecessary;
    }

    //! @}
    //! @name  Molar Thermodynamic Properties of the Solution
    //! @{

    /// Molar enthalpy. Units: J/kmol.
    virtual doublereal enthalpy_mole() const {
        return err("enthalpy_mole");
    }

    /// Molar internal energy. Units: J/kmol.
    virtual doublereal intEnergy_mole() const {
        return enthalpy_mole() - pressure()* molarVolume();
    }

    /// Molar entropy. Units: J/kmol/K.
    virtual doublereal entropy_mole() const {
        return err("entropy_mole");
    }

    /// Molar Gibbs function. Units: J/kmol.
    virtual doublereal gibbs_mole() const {
        return enthalpy_mole() - temperature()*entropy_mole();
    }

    /// Molar heat capacity at constant pressure. Units: J/kmol/K.
    virtual doublereal cp_mole() const {
        return err("cp_mole");
    }

    /// Molar heat capacity at constant volume. Units: J/kmol/K.
    virtual doublereal cv_mole() const {
        return err("cv_mole");
    }

    /**
     * @returns species vibrational specific heat at
     * constant volume.
     */
    /// Molar heat capacity at constant volume. Units: J/kmol/K.
    virtual doublereal cv_vib(int, double) const {
        return err("cv_vib");
    }

    //! @}
    //! @name Mechanical Properties
    //! @{

    //! Return the thermodynamic pressure (Pa).
    /*!
     *  This method must be overloaded in derived classes. Since the
     *  mass density, temperature, and mass fractions are stored,
     *  this method should use these values to implement the
     *  mechanical equation of state \f$ P(T, \rho, Y_1, \dots,
     *  Y_K) \f$.
     */
    virtual doublereal pressure() const {
        return err("pressure");
    }

    //! Set the internally stored pressure (Pa) at constant
    //! temperature and composition
    /*!
     *   This method must be reimplemented in derived classes, where it
     *   may involve the solution of a nonlinear equation. Within %Cantera,
     *   the independent variable is the density. Therefore, this function
     *   solves for the density that will yield the desired input pressure.
     *   The temperature and composition iare held constant during this process.
     *
     *  This base class function will print an error, if not overwritten.
     *
     *  @param p input Pressure (Pa)
     */
    virtual void setPressure(doublereal p) {
        err("setPressure");
    }

    //! Returns  the isothermal compressibility. Units: 1/Pa.
    /*!
     * The isothermal compressibility is defined as
     * \f[
     * \kappa_T = -\frac{1}{v}\left(\frac{\partial v}{\partial P}\right)_T
     * \f]
     *  or
     * \f[
     * \kappa_T = \frac{1}{\rho}\left(\frac{\partial \rho}{\partial P}\right)_T
     * \f]
     */
    virtual doublereal isothermalCompressibility() const {
        err("isothermalCompressibility");
        return -1.0;
    }

    //! Return the volumetric thermal expansion coefficient. Units: 1/K.
    /*!
     * The thermal expansion coefficient is defined as
     * \f[
     * \beta = \frac{1}{v}\left(\frac{\partial v}{\partial T}\right)_P
     * \f]
     */
    virtual doublereal thermalExpansionCoeff() const {
        err("thermalExpansionCoeff()");
        return -1.0;
    }

    /**
     * @}
     * @name Electric Potential
     *
     * The phase may be at some non-zero electrical
     * potential. These methods set or get the value of the
     * electric potential.
     */
    //@{

    //! Set the electric potential of this phase (V).
    /*!
     * This is used by classes InterfaceKinetics and EdgeKinetics to
     * compute the rates of charge-transfer reactions, and in computing
     * the electrochemical potentials of the species.
     *
     * Each phase may have its own electric potential.
     *
     * @param v Input value of the electric potential in Volts
     */
    void setElectricPotential(doublereal v) {
        m_phi = v;
    }

    //! Returns the electric potential of this phase (V).
    /*!
     *  Units are Volts (which are Joules/coulomb)
     */
    doublereal electricPotential() const {
        return m_phi;
    }

    /**
     * @}
     * @name Activities, Standard States, and Activity Concentrations
     *
     * The activity \f$a_k\f$ of a species in solution is related
     * to the chemical potential by \f[ \mu_k = \mu_k^0(T,P) +
     * \hat R T \log a_k. \f] The quantity \f$\mu_k^0(T,P)\f$ is
     * the standard chemical potential at unit activity,
     * which depends on  temperature and pressure,
     * but not on composition. The
     * activity is dimensionless.
     * @{
     */


    //! This method returns the convention used in specification
    //! of the activities, of which there are currently two, molar-
    //! and molality-based conventions.
    /*!
     * Currently, there are two activity conventions:
     *  - Molar-based activities
     *       %Unit activity of species at either a hypothetical pure
     *       solution of the species or at a hypothetical
     *       pure ideal solution at infinite dilution
     *   cAC_CONVENTION_MOLAR 0
     *      - default
     *
     *  - Molality-based activities
     *       (unit activity of solutes at a hypothetical 1 molal
     *        solution referenced to infinite dilution at all
     *        pressures and temperatures).
     *   cAC_CONVENTION_MOLALITY 1
     */
    virtual int activityConvention() const;

    //! This method returns the convention used in specification
    //! of the standard state, of which there are currently two,
    //! temperature based, and variable pressure based.
    /*!
     * Currently, there are two standard state conventions:
     *  - Temperature-based activities
     *   cSS_CONVENTION_TEMPERATURE 0
     *      - default
     *
     *  -  Variable Pressure and Temperature -based activities
     *   cSS_CONVENTION_VPSS 1
     *
     *  -  Thermodynamics is set via slave ThermoPhase objects with
     *     nothing being carried out at this %ThermoPhase object level
     *   cSS_CONVENTION_SLAVE 2
     */
    virtual int standardStateConvention() const;

    //! This method returns an array of generalized concentrations
    /*!
     * \f$ C^a_k\f$ are defined such that \f$ a_k = C^a_k /
     * C^0_k, \f$ where \f$ C^0_k \f$ is a standard concentration
     * defined below and \f$ a_k \f$ are activities used in the
     * thermodynamic functions.  These activity (or generalized)
     * concentrations are used
     * by kinetics manager classes to compute the forward and
     * reverse rates of elementary reactions. Note that they may
     * or may not have units of concentration --- they might be
     * partial pressures, mole fractions, or surface coverages,
     * for example.
     *
     * @param c Output array of generalized concentrations. The
     *           units depend upon the implementation of the
     *           reaction rate expressions within the phase.
     */
    virtual void getActivityConcentrations(doublereal* c) const {
        err("getActivityConcentrations");
    }

    //! Return the standard concentration for the kth species
    /*!
     * The standard concentration \f$ C^0_k \f$ used to normalize
     * the activity (i.e., generalized) concentration. In many cases, this quantity
     * will be the same for all species in a phase - for example,
     * for an ideal gas \f$ C^0_k = P/\hat R T \f$. For this
     * reason, this method returns a single value, instead of an
     * array.  However, for phases in which the standard
     * concentration is species-specific (e.g. surface species of
     * different sizes), this method may be called with an
     * optional parameter indicating the species.
     *
     * @param k Optional parameter indicating the species. The default
     *          is to assume this refers to species 0.
     * @return
     *   Returns the standard concentration. The units are by definition
     *   dependent on the ThermoPhase and kinetics manager representation.
     */
    virtual doublereal standardConcentration(size_t k=0) const {
        err("standardConcentration");
        return -1.0;
    }

    //! Natural logarithm of the standard concentration of the kth species.
    /*!
     * @param k    index of the species (defaults to zero)
     */
    virtual doublereal logStandardConc(size_t k=0) const;

    //! Returns the units of the standard and generalized concentrations.
    /*!
     * Note they have the same units, as their
     * ratio is defined to be equal to the activity of the kth
     * species in the solution, which is unitless.
     *
     * This routine is used in print out applications where the
     * units are needed. Usually, MKS units are assumed throughout
     * the program and in the XML input files.
     *
     * The base %ThermoPhase class assigns the default quantities
     * of (kmol/m3) for all species.
     * Inherited classes are responsible for overriding the default
     * values if necessary.
     *
     * On return uA contains the powers of the units (MKS assumed)
     * of the standard concentrations and generalized concentrations
     * for the kth species.
     *
     * @param uA Output vector containing the units
     *  uA[0] = kmol units - default  = 1
     *  uA[1] = m    units - default  = -nDim(), the number of spatial
     *                                dimensions in the Phase class.
     *  uA[2] = kg   units - default  = 0;
     *  uA[3] = Pa(pressure) units - default = 0;
     *  uA[4] = Temperature units - default = 0;
     *  uA[5] = time units - default = 0
     * @param k species index. Defaults to 0.
     * @param sizeUA output int containing the size of the vector.
     *        Currently, this is equal to 6.
     * @deprecated
     */
    virtual void getUnitsStandardConc(double* uA, int k = 0,
                                      int sizeUA = 6) const;

    //! Get the array of non-dimensional activities at
    //! the current solution temperature, pressure, and solution concentration.
    /*!
     * Note, for molality based formulations, this returns the
     * molality based activities.
     *
     * We resolve this function at this level by calling
     * on the activityConcentration function. However,
     * derived classes may want to override this default
     * implementation.
     *
     * @param a   Output vector of activities. Length: m_kk.
     */
    virtual void getActivities(doublereal* a) const;

    //! Get the array of non-dimensional molar-based activity coefficients at
    //! the current solution temperature, pressure, and solution concentration.
    /*!
     * @param ac Output vector of activity coefficients. Length: m_kk.
     */
    virtual void getActivityCoefficients(doublereal* ac) const {
        if (m_kk == 1) {
            ac[0] = 1.0;
        } else {
            err("getActivityCoefficients");
        }
    }

    //! Get the array of non-dimensional molar-based ln activity coefficients at
    //! the current solution temperature, pressure, and solution concentration.
    /*!
     * @param lnac Output vector of ln activity coefficients. Length: m_kk.
     */
    virtual void getLnActivityCoefficients(doublereal* lnac) const;

    //@}
    /// @name  Partial Molar Properties of the Solution
    //@{

    /**
     * Get the array of non-dimensional species chemical potentials
     * These are partial molar Gibbs free energies.
     * \f$ \mu_k / \hat R T \f$.
     * Units: unitless
     *
     * @param mu  Output vector of dimensionless chemical potentials.
     *            Length: m_kk.
     */
    virtual void getChemPotentials_RT(doublereal* mu) const {
        err("getChemPotentials_RT");
    }


    //! Get the species chemical potentials. Units: J/kmol.
    /*!
     * This function returns a vector of chemical potentials of the
     * species in solution at the current temperature, pressure
     * and mole fraction of the solution.
     *
     * @param mu  Output vector of species chemical
     *            potentials. Length: m_kk. Units: J/kmol
     */
    virtual void getChemPotentials(doublereal* mu) const {
        err("getChemPotentials");
    }

    //!  Get the species electrochemical potentials.
    /*!
     *  These are partial molar quantities.  This method adds a term \f$ F z_k
     *  \phi_p \f$ to each chemical potential.
     *  The electrochemical potential of species k in a phase p, \f$ \zeta_k \f$,
     *  is related to the chemical potential via
     *  the following equation,
     *
     *       \f[
     *            \zeta_{k}(T,P) = \mu_{k}(T,P) + F z_k \phi_p
     *       \f]
     *
     * @param mu  Output vector of species electrochemical
     *            potentials. Length: m_kk. Units: J/kmol
     */
    void getElectrochemPotentials(doublereal* mu) const {
        getChemPotentials(mu);
        double ve = Faraday * electricPotential();
        for (size_t k = 0; k < m_kk; k++) {
            mu[k] += ve*charge(k);
        }
    }

    //! Returns an array of partial molar enthalpies for the species
    //! in the mixture. Units (J/kmol)
    /*!
     * @param hbar    Output vector of species partial molar enthalpies.
     *                Length: m_kk. units are J/kmol.
     */
    virtual void getPartialMolarEnthalpies(doublereal* hbar) const {
        err("getPartialMolarEnthalpies");
    }

    //! Returns an array of partial molar entropies of the species in the
    //! solution. Units: J/kmol/K.
    /*!
     * @param sbar    Output vector of species partial molar entropies.
     *                Length = m_kk. units are J/kmol/K.
     */
    virtual void getPartialMolarEntropies(doublereal* sbar) const {
        err("getPartialMolarEntropies");
    }

    //! Return an array of partial molar internal energies for the
    //! species in the mixture.  Units: J/kmol.
    /*!
     * @param ubar    Output vector of species partial molar internal energies.
     *                Length = m_kk. units are J/kmol.
     */
    virtual void getPartialMolarIntEnergies(doublereal* ubar) const {
        err("getPartialMolarIntEnergies");
    }

    //! Return an array of partial molar heat capacities for the
    //! species in the mixture.  Units: J/kmol/K
    /*!
     * @param cpbar   Output vector of species partial molar heat
     *                capacities at constant pressure.
     *                Length = m_kk. units are J/kmol/K.
     */
    virtual void getPartialMolarCp(doublereal* cpbar) const {
        err("getPartialMolarCp");
    }

    //! Return an array of partial molar volumes for the
    //! species in the mixture. Units: m^3/kmol.
    /*!
     *  @param vbar   Output vector of species partial molar volumes.
     *                Length = m_kk. units are m^3/kmol.
     */
    virtual void getPartialMolarVolumes(doublereal* vbar) const {
        err("getPartialMolarVolumes");
    }

    //! Return an array of derivatives of partial molar volumes wrt temperature for the
    //! species in the mixture. Units: m^3/kmol.
    /*!
     *  The derivative is at constant pressure
     *
     *  @param d_vbar_dT   Output vector of derivatives of species partial molar volumes wrt T.
     *                     Length = m_kk. units are m^3/kmol/K.
     */
    virtual void getdPartialMolarVolumes_dT(doublereal* d_vbar_dT) const {
        err("getdPartialMolarVolumes_dT");
    }

    //! Return an array of derivatives of partial molar volumes wrt pressure  for the
    //! species in the mixture. Units: m^3/kmol.
    /*!
     *  The derivative is at constant temperature
     *
     *  @param d_vbar_dP   Output vector of derivatives of species partial molar volumes wrt P.
     *                     Length = m_kk. units are m^3/kmol/Pa.
     */
    virtual void getdPartialMolarVolumes_dP(doublereal* d_vbar_dP) const {
        err("getdPartialMolarVolumes_dP");
    }

    //@}
    /// @name Properties of the Standard State of the Species in the Solution
    //@{

    //! Get the array of chemical potentials at unit activity for the species
    //! at their standard states at the current <I>T</I> and <I>P</I> of the solution.
    /*!
     * These are the standard state chemical potentials \f$ \mu^0_k(T,P)
     * \f$. The values are evaluated at the current
     * temperature and pressure of the solution
     *
     * @param mu      Output vector of chemical potentials.
     *                Length: m_kk.
     */
    virtual void getStandardChemPotentials(doublereal* mu) const {
        err("getStandardChemPotentials");
    }

    //! Get the nondimensional Enthalpy functions for the species
    //! at their standard states at the current <I>T</I> and <I>P</I> of the solution.
    /*!
     * @param hrt      Output vector of  nondimensional standard state enthalpies.
     *                 Length: m_kk.
     */
    virtual void getEnthalpy_RT(doublereal* hrt) const {
        err("getEnthalpy_RT");
    }

    //! Get the array of nondimensional Entropy functions for the
    //! standard state species at the current <I>T</I> and <I>P</I> of the solution.
    /*!
     * @param sr   Output vector of  nondimensional standard state entropies.
     *             Length: m_kk.
     */
    virtual void getEntropy_R(doublereal* sr) const {
        err("getEntropy_R");
    }

    //! Get the nondimensional Gibbs functions for the species
    //! in their standard states at the current <I>T</I> and <I>P</I> of the solution.
    /*!
     * @param grt  Output vector of nondimensional standard state gibbs free energies
     *             Length: m_kk.
     */
    virtual void getGibbs_RT(doublereal* grt) const {
        err("getGibbs_RT");
    }

    //! Get the Gibbs functions for the standard
    //! state of the species at the current <I>T</I> and <I>P</I> of the solution
    /*!
     * Units are Joules/kmol
     * @param gpure  Output vector of  standard state gibbs free energies
     *               Length: m_kk.
     */
    virtual void getPureGibbs(doublereal* gpure) const {
        err("getPureGibbs");
    }

    //!  Returns the vector of nondimensional Internal Energies  of the standard
    //!  state species at the current <I>T</I> and <I>P</I> of the solution
    /*!
     * @param urt  output vector of nondimensional standard state internal energies
     *             of the species. Length: m_kk.
     */
    virtual void getIntEnergy_RT(doublereal* urt) const {
        err("getIntEnergy_RT");
    }

    //! Get the nondimensional Heat Capacities at constant
    //! pressure for the species standard states
    //! at the current <I>T</I> and <I>P</I> of the solution
    /*!
     * @param cpr   Output vector of nondimensional standard state heat capacities
     *              Length: m_kk.
     */
    virtual void getCp_R(doublereal* cpr) const {
        err("getCp_R");
    }

    //!  Get the molar volumes of the species standard states at the current
    //!  <I>T</I> and <I>P</I> of the solution.
    /*!
     * units = m^3 / kmol
     *
     * @param vol     Output vector containing the standard state volumes.
     *                Length: m_kk.
     */
    virtual void getStandardVolumes(doublereal* vol) const {
        err("getStandardVolumes");
    }

    //!  Get the derivative of the molar volumes of the species standard states wrt temperature at the current
    //!  <I>T</I> and <I>P</I> of the solution.
    /*!
     *  The derivative is at constant pressure
     *   units = m^3 / kmol / K
     *
     * @param d_vol_dT Output vector containing derivatives of standard state volumes wrt T
     *                 Length: m_kk.
     */
    virtual void getdStandardVolumes_dT(doublereal* d_vol_dT) const {
        err("getdStandardVolumes_dT");
    }

    //!  Get the derivative molar volumes of the species standard states wrt pressure at the current
    //!  <I>T</I> and <I>P</I> of the solution.
    /*!
     *  The derivative is at constant temperature.
     * units = m^3 / kmol / Pa
     *
     * @param d_vol_dP  Output vector containing the derivative of standard state volumes wrt P.
     *                  Length: m_kk.
     */
    virtual void getdStandardVolumes_dP(doublereal* d_vol_dP) const {
        err("getdStandardVolumes_dP");
    }

    //@}
    /// @name Thermodynamic Values for the Species Reference States
    //@{

    //!  Returns the vector of nondimensional
    //!  enthalpies of the reference state at the current temperature
    //!  of the solution and the reference pressure for the species.
    /*!
     *  This base function will throw a CanteraException unless
     *  it is overwritten in a derived class.
     *
     * @param hrt     Output vector containing the nondimensional reference state
     *                enthalpies
     *                Length: m_kk.
     */
    virtual void getEnthalpy_RT_ref(doublereal* hrt) const {
        err("getEnthalpy_RT_ref");
    }

    //!  Returns the vector of nondimensional
    //!  Gibbs Free Energies of the reference state at the current temperature
    //!  of the solution and the reference pressure for the species.
    /*!
     * @param grt     Output vector containing the nondimensional reference state
     *                Gibbs Free energies.  Length: m_kk.
     */
    virtual void getGibbs_RT_ref(doublereal* grt) const {
        err("getGibbs_RT_ref");
    }

    //!  Returns the vector of the
    //!  gibbs function of the reference state at the current temperature
    //!  of the solution and the reference pressure for the species.
    /*!
     *  units = J/kmol
     *
     * @param g       Output vector containing the  reference state
     *                Gibbs Free energies.  Length: m_kk. Units: J/kmol.
     */
    virtual void getGibbs_ref(doublereal* g) const {
        err("getGibbs_ref");
    }

    //!  Returns the vector of nondimensional
    //!  entropies of the reference state at the current temperature
    //!  of the solution and the reference pressure for each species.
    /*!
     * @param er      Output vector containing the nondimensional reference state
     *                entropies.  Length: m_kk.
     */
    virtual void getEntropy_R_ref(doublereal* er) const {
        err("getEntropy_R_ref");
    }

    //! Returns the vector of nondimensional
    //!  internal Energies of the reference state at the current temperature
    //!  of the solution and the reference pressure for each species.
    /*!
     * @param urt    Output vector of nondimensional reference state
     *               internal energies of the species.
     *               Length: m_kk
     */
    virtual void getIntEnergy_RT_ref(doublereal* urt) const {
        err("getIntEnergy_RT_ref");
    }

    //!  Returns the vector of nondimensional
    //!  constant pressure heat capacities of the reference state
    //!  at the current temperature of the solution
    //!  and reference pressure for each species.
    /*!
     * @param cprt   Output vector of nondimensional reference state
     *               heat capacities at constant pressure for the species.
     *               Length: m_kk
     */
    virtual void getCp_R_ref(doublereal* cprt) const {
        err("getCp_R_ref()");
    }

    //!  Get the molar volumes of the species reference states at the current
    //!  <I>T</I> and <I>P_ref</I> of the solution.
    /*!
     * units = m^3 / kmol
     *
     * @param vol     Output vector containing the standard state volumes.
     *                Length: m_kk.
     */
    virtual void getStandardVolumes_ref(doublereal* vol) const {
        err("getStandardVolumes_ref");
    }

    //! Sets the reference composition
    /*!
     *  @param x   Mole fraction vector to set the reference composition to.
     *             If this is zero, then the reference mole fraction
     *             is set to the current mole fraction vector.
     */
    virtual void setReferenceComposition(const doublereal* const x);

    //! Gets the reference composition
    /*!
     *  The reference mole fraction is a safe mole fraction.
     *  @param x   Mole fraction vector containing the reference composition.
     */
    virtual void getReferenceComposition(doublereal* const x) const;

    //
    //  The methods below are not virtual, and should not
    //  be overloaded.
    //

    //@}
    //! @name Specific Properties
    //@{

    /**
     * Specific enthalpy. Units: J/kg.
     */
    doublereal enthalpy_mass() const {
        return enthalpy_mole()/meanMolecularWeight();
    }

    /**
     * Specific internal energy. Units: J/kg.
     */
    doublereal intEnergy_mass() const {
        return intEnergy_mole()/meanMolecularWeight();
    }

    /**
     * Specific entropy. Units: J/kg/K.
     */
    doublereal entropy_mass() const {
        return entropy_mole()/meanMolecularWeight();
    }

    /**
     * Specific Gibbs function. Units: J/kg.
     */
    doublereal gibbs_mass() const {
        return gibbs_mole()/meanMolecularWeight();
    }

    /**
     * Specific heat at constant pressure. Units: J/kg/K.
     */
    doublereal cp_mass() const {
        return cp_mole()/meanMolecularWeight();
    }

    /**
     * Specific heat at constant volume. Units: J/kg/K.
     */
    doublereal cv_mass() const {
        return cv_mole()/meanMolecularWeight();
    }
    //@}

    //! Return the Gas Constant multiplied by the current temperature
    /*!
     *  The units are Joules kmol-1
     */
    doublereal _RT() const {
        return temperature() * GasConstant;
    }

    /**
     * @name Setting the State
     *
     * These methods set all or part of the thermodynamic
     * state.
     * @{
     */

    //! Set the temperature (K), pressure (Pa), and mole fractions.
    /*!
     * Note, the mole fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param t    Temperature (K)
     * @param p    Pressure (Pa)
     * @param x    Vector of mole fractions.
     *             Length is equal to m_kk.
     */
    virtual void setState_TPX(doublereal t, doublereal p, const doublereal* x);

    //! Set the temperature (K), pressure (Pa), and mole fractions.
    /*!
     * Note, the mole fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param t    Temperature (K)
     * @param p    Pressure (Pa)
     * @param x    Composition map of mole fractions. Species not in
     *             the composition map are assumed to have zero mole fraction
     */
    virtual void setState_TPX(doublereal t, doublereal p, compositionMap& x);

    //! Set the temperature (K), pressure (Pa), and mole fractions.
    /*!
     * Note, the mole fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param t    Temperature (K)
     * @param p    Pressure (Pa)
     * @param x    String containing a composition map of the mole fractions. Species not in
     *             the composition map are assumed to have zero mole fraction
     */
    virtual void setState_TPX(doublereal t, doublereal p, const std::string& x);

    //! Set the internally stored temperature (K), pressure (Pa), and mass fractions of the phase.
    /*!
     * Note, the mass fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param t    Temperature (K)
     * @param p    Pressure (Pa)
     * @param y    Vector of mass fractions.
     *             Length is equal to m_kk.
     */
    virtual void setState_TPY(doublereal t, doublereal p, const doublereal* y);

    //! Set the internally stored temperature (K), pressure (Pa), and mass fractions of the phase
    /*!
     * Note, the mass fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param t    Temperature (K)
     * @param p    Pressure (Pa)
     * @param y    Composition map of mass fractions. Species not in
     *             the composition map are assumed to have zero mass fraction
     */
    virtual void setState_TPY(doublereal t, doublereal p, compositionMap& y);

    //! Set the internally stored temperature (K), pressure (Pa), and mass fractions of the phase
    /*!
     * Note, the mass fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param t    Temperature (K)
     * @param p    Pressure (Pa)
     * @param y    String containing a composition map of the mass fractions. Species not in
     *             the composition map are assumed to have zero mass fraction
     */
    virtual void setState_TPY(doublereal t, doublereal p, const std::string& y);

    //! Set the temperature (K) and pressure (Pa)
    /*!
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param t    Temperature (K)
     * @param p    Pressure (Pa)
     */
    virtual void setState_TP(doublereal t, doublereal p);

    //! Set the pressure (Pa) and mole fractions.
    /*!
     * Note, the mole fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param p    Pressure (Pa)
     * @param x    Vector of mole fractions.
     *             Length is equal to m_kk.
     */
    virtual void setState_PX(doublereal p, doublereal* x);

    //! Set the internally stored pressure (Pa) and mass fractions.
    /*!
     * Note, the temperature is held constant during this operation.
     * Note, the mass fractions are set first before the pressure is set.
     * Setting the pressure may involve the solution of a nonlinear equation.
     *
     * @param p    Pressure (Pa)
     * @param y    Vector of mass fractions.
     *             Length is equal to m_kk.
     */
    virtual void setState_PY(doublereal p, doublereal* y);

    //! Set the internally stored specific enthalpy (J/kg) and pressure (Pa) of the phase.
    /*!
     * @param h     Specific enthalpy (J/kg)
     * @param p     Pressure (Pa)
     * @param tol   Optional parameter setting the tolerance of the calculation.
     *              Important for some applications where numerical Jacobians
     *              are being calculated.Defaults to 1.0E-4
     */
    virtual void setState_HP(doublereal h, doublereal p, doublereal tol = 1.e-4);

    //! Set the specific internal energy (J/kg) and specific volume (m^3/kg).
    /*!
     * This function fixes the internal state of the phase so that
     * the specific internal energy and specific volume have the value of the input parameters.
     *
     * @param u    specific internal energy (J/kg)
     * @param v    specific volume (m^3/kg).
     * @param tol  Optional parameter setting the tolerance of the calculation.
     *             Important for some applications where numerical Jacobians
     *             are being calculated.Defaults to 1.0E-4
     */
    virtual void setState_UV(doublereal u, doublereal v, doublereal tol = 1.e-4);

private:

    //! Carry out work in HP and UV calculations.
    /*!
     * @param h     Specific enthalpy or internal energy (J/kg)
     * @param p     Pressure (Pa) or specific volume (m^3/kg)
     * @param tol   Optional parameter setting the tolerance of the calculation.
     *              Defaults to 1.0E-4. Important for some applications where
     *              numerical Jacobians are being calculated.
     * @param doUV  True if solving for UV, false for HP.
     */
    void setState_HPorUV(doublereal h, doublereal p,
                         doublereal tol = 1.e-4, bool doUV = false);

public:

    //! Set the specific entropy (J/kg/K) and pressure (Pa).
    /*!
     * This function fixes the internal state of the phase so that
     * the specific entropy and the pressure have the value of the input parameters.
     *
     * @param s    specific entropy (J/kg/K)
     * @param p    specific pressure (Pa).
     * @param tol   Optional parameter setting the tolerance of the calculation.
     *              Defaults to 1.0E-4. Important for some applications where
     *              numerical Jacobians are being calculated.
     */
    virtual void setState_SP(doublereal s, doublereal p, doublereal tol = 1.e-4);

    //! Set the specific entropy (J/kg/K) and specific volume (m^3/kg).
    /*!
     * This function fixes the internal state of the phase so that
     * the specific entropy and specific volume have the value of the input parameters.
     *
     * @param s    specific entropy (J/kg/K)
     * @param v    specific volume (m^3/kg).
     * @param tol   Optional parameter setting the tolerance of the calculation.
     *              Defaults to 1.0E-4. Important for some applications where
     *              numerical Jacobians are being calculated.
     */
    virtual void setState_SV(doublereal s, doublereal v, doublereal tol = 1.e-4);

private:

    //! Carry out work in SP and SV calculations.
    /*!
     * @param s     Specific entropy (J/kg)
     * @param p     Pressure (Pa) or specific volume (m^3/kg)
     * @param tol   Optional parameter setting the tolerance of the calculation.
     *              Defaults to 1.0E-4. Important for some applications where
     *              numerical Jacobians are being calculated.
     * @param doSV  True if solving for SV, false for SP.
     */
    void setState_SPorSV(doublereal s, doublereal p,
                         doublereal tol = 1.e-4, bool doSV = false);

    //! Helper function used by setState_HPorUV and setState_SPorSV.
    //! Sets the temperature and (if set_p is true) the pressure.
    void setState_conditional_TP(doublereal t, doublereal p, bool set_p);
public:

    //@}

    /**
     * @name Chemical Equilibrium
     * Chemical equilibrium.
     * @{
     */


    //!This method is used by the ChemEquil equilibrium solver.
    /*!
     * It sets the state such that the chemical potentials satisfy
     * \f[ \frac{\mu_k}{\hat R T} = \sum_m A_{k,m}
     * \left(\frac{\lambda_m} {\hat R T}\right) \f] where
     * \f$ \lambda_m \f$ is the element potential of element m. The
     * temperature is unchanged.  Any phase (ideal or not) that
     * implements this method can be equilibrated by ChemEquil.
     *
     * @param lambda_RT Input vector of dimensionless element potentials
     *                  The length is equal to nElements().
     */
    virtual void setToEquilState(const doublereal* lambda_RT) {
        err("setToEquilState");
    }

    //! Stores the element potentials in the ThermoPhase object
    /*!
     * Called by function 'equilibrate' in ChemEquil.h to transfer
     * the element potentials to this object after every successful
     *  equilibration routine.
     * The element potentials are stored in their dimensionless
     * forms, calculated by dividing by RT.
     *
     *    @param lambda Input vector containing the element potentials.
     *           Length = nElements. Units are Joules/kmol.
     */
    void setElementPotentials(const vector_fp& lambda);


    //!  Returns the element potentials stored in the ThermoPhase object
    /*!
     * Returns the stored element potentials.
     * The element potentials are retrieved from their stored
     * dimensionless forms by multiplying by RT.
     * @param lambda Output vector containing the element potentials.
     *        Length = nElements. Units are Joules/kmol.
     * @return bool indicating whether there are any valid stored element
     *         potentials. The calling routine should check this
     *         bool. In the case that there aren't any, lambda is not
     *         touched.
     */
    bool getElementPotentials(doublereal* lambda) const;

    //@}


    //---------------------------------------------------------
    /// @name Critical State Properties.
    /// These methods are only implemented by some subclasses, and may
    /// be moved out of ThermoPhase at a later date.

    //@{

    /// Critical temperature (K).
    virtual doublereal critTemperature() const {
        err("critTemperature");
        return -1.0;
    }

    /// Critical pressure (Pa).
    virtual doublereal critPressure() const {
        err("critPressure");
        return -1.0;
    }

    /// Critical density (kg/m3).
    virtual doublereal critDensity() const {
        err("critDensity");
        return -1.0;
    }

    //@}

    /** @name Saturation Properties.
     *
     * These methods are only implemented by subclasses that
     * implement full liquid-vapor equations of state. They may be
     * moved out of %ThermoPhase at a later date.
     */
    //@{

    //! Return the saturation temperature given the pressure
    /*!
     * @param p Pressure (Pa)
     */
    virtual doublereal satTemperature(doublereal p) const {
        err("satTemperature");
        return -1.0;
    }

    //! Return the saturation pressure given the temperature
    /*!
     * @param t Temperature (Kelvin)
     */
    virtual doublereal satPressure(doublereal t) {
        err("satPressure");
        return -1.0;
    }

    //! Return the fraction of vapor at the current conditions
    virtual doublereal vaporFraction() const {
        err("vaprFraction");
        return -1.0;
    }

    //! Set the state to a saturated system at a particular temperature
    /*!
     * @param t  Temperature (kelvin)
     * @param x  Fraction of vapor
     */
    virtual void setState_Tsat(doublereal t, doublereal x) {
        err("setState_sat");
    }

    //! Set the state to a saturated system at a particular pressure
    /*!
     * @param p  Pressure (Pa)
     * @param x  Fraction of vapor
     */
    virtual void setState_Psat(doublereal p, doublereal x) {
        err("setState_sat");
    }

    //@}


    //! @name Initialization Methods - For Internal Use (%ThermoPhase)
    /*!
     * The following methods are used in the process of constructing
     * the phase and setting its parameters from a specification in an
     * input file. They are not normally used in application programs.
     * To see how they are used,
     * see files importCTML.cpp and  ThermoFactory.cpp.
     */
    //@{

    //! Store a reference pointer to the XML tree containing the species data
    //! for this phase.
    /*!
     *   This is used to access data needed to construct transport manager later.
     *   @internal
     *
     * @param k      Species index
     * @param data   Pointer to the XML_Node data containing
     *               information about the species in the phase.
     */
    void saveSpeciesData(const size_t k, const XML_Node* const data);

    //!  Return a pointer to the vector of XML nodes containing the species
    //!  data for this phase.
    const std::vector<const XML_Node*> & speciesData() const;

    //!  Install a species thermodynamic property manager.
    /*!
     * The species thermodynamic property manager
     * computes properties of the pure species for use in
     * constructing solution properties. It is meant for internal
     * use, and some classes derived from ThermoPhase may not use
     * any species thermodynamic property manager. This method is
     * called by function importPhase() in importCTML.cpp.
     *
     * @param spthermo input pointer to the species thermodynamic property
     *                 manager.
     *
     *  @internal
     */
    void setSpeciesThermo(SpeciesThermo* spthermo);

    //! Return a changeable reference to the calculation manager
    //! for species reference-state thermodynamic properties
    /*!
     *
     * @param k   Species id. The default is -1, meaning return the default
     *
     * @internal
     */
    virtual SpeciesThermo& speciesThermo(int k = -1);

    /**
     * @internal
     * Initialization of a ThermoPhase object using an
     * ctml file.
     *
     *   This routine is a precursor to initThermoXML(XML_Node*)
     *   routine, which does most of the work.
     *   Here we read extra information about the XML description
     *   of a phase. Regular information about elements and species
     *   and their reference state thermodynamic information
     *   have already been read at this point.
     *   For example, we do not need to call this function for
     *   ideal gas equations of state.
     *
     * @param inputFile XML file containing the description of the
     *        phase
     *
     * @param id  Optional parameter identifying the name of the
     *            phase. If none is given, the first XML
     *            phase element encountered will be used.
     */
    virtual void initThermoFile(const std::string& inputFile,
                                const std::string& id);

    //!Import and initialize a ThermoPhase object  using an XML tree.
    /*!
     * @internal
     *
     *   Here we read extra information about the XML description
     *   of a phase. Regular information about elements and species
     *   and their reference state thermodynamic information
     *   have already been read at this point.
     *   For example, we do not need to call this function for
     *   ideal gas equations of state. This function is called from importPhase()
     *   after the elements and the species are initialized with
     *   default ideal solution level data.
     *
     *   The default implementation in ThermoPhase calls the
     *   virtual function initThermo() and then sets the "state" of the
     *   phase by looking for an XML element named "state", and then
     *   interpreting its contents by calling the virtual function
     *   setStateFromXML().
     *
     * @param phaseNode This object must be the phase node of a
     *             complete XML tree
     *             description of the phase, including all of the
     *             species data. In other words while "phase" must
     *             point to an XML phase object, it must have
     *             sibling nodes "speciesData" that describe
     *             the species in the phase.
     * @param id   ID of the phase. If nonnull, a check is done
     *             to see if phaseNode is pointing to the phase
     *             with the correct id.
     */
    virtual void initThermoXML(XML_Node& phaseNode, const std::string& id);

    //! Initialize the ThermoPhase object after all species have been set up
    /*!
     * @internal Initialize.
     *
     * This method is provided to allow
     * subclasses to perform any initialization required after all
     * species have been added. For example, it might be used to
     * resize internal work arrays that must have an entry for
     * each species.  The base class implementation does nothing,
     * and subclasses that do not require initialization do not
     * need to overload this method.  When importing a CTML phase
     * description, this method is called from ThermoPhase::initThermoXML(),
     * which is called from importPhase(),
     * just prior to returning from function importPhase().
     *
     * @see importCTML.cpp
     */
    virtual void initThermo();

    //! Add in species from Slave phases
    /*!
     *  This hook is used for  cSS_CONVENTION_SLAVE phases
     *
     *  @param phaseNode   XML Element for the phase
     */
    virtual void installSlavePhases(Cantera::XML_Node* phaseNode);

    //! Set the equation of state parameters
    /*!
     * @internal
     *  The number and meaning of these depends on the subclass.
     *
     * @param n number of parameters
     * @param c array of \a n coefficients
     * @deprecated Use methods specific to the derived class
     */
    virtual void setParameters(int n, doublereal* const c) {
        warn_deprecated("ThermoPhase::setParameters");
    }


    //! Get the equation of state parameters in a vector
    /*!
     * @internal
     * The number and meaning of these depends on the subclass.
     *
     * @param n number of parameters
     * @param c array of \a n coefficients
     * @deprecated Use methods specific to the derived class
     */
    virtual void getParameters(int& n, doublereal* const c) const {
        warn_deprecated("ThermoPhase::getParameters");
    }


    //! Set equation of state parameter values from XML entries.
    /*!
     *
     * This method is called by function importPhase() in
     * file importCTML.cpp when processing a phase definition in
     * an input file. It should be overloaded in subclasses to set
     * any parameters that are specific to that particular phase
     * model. Note, this method is called before the phase is
     * initialized with elements and/or species.
     *
     * @param eosdata An XML_Node object corresponding to
     *                the "thermo" entry for this phase in the input file.
     */
    virtual void setParametersFromXML(const XML_Node& eosdata) {}


    //! Set the initial state of the phase to the conditions
    //! specified in the state XML element.
    /*!
     *
     * This method sets the temperature, pressure, and mole
     * fraction vector to a set default value.
     *
     * @param state AN XML_Node object corresponding to
     *              the "state" entry for this phase in the
     *              input file.
     */
    virtual void setStateFromXML(const XML_Node& state);

    //! @}
    //! @name  Derivatives of Thermodynamic Variables needed for Applications
    //! @{

    //! Get the change in activity coefficients wrt changes in state (temp, mole fraction, etc) along
    //! a line in parameter space or along a line in physical space
    /*!
     *
     * @param dTds           Input of temperature change along the path
     * @param dXds           Input vector of changes in mole fraction along the path. length = m_kk
     *                       Along the path length it must be the case that the mole fractions sum to one.
     * @param dlnActCoeffds  Output vector of the directional derivatives of the
     *                       log Activity Coefficients along the path. length = m_kk
     *                       units are 1/units(s). if s is a physical coordinate then the units are 1/m.
     */
    virtual void getdlnActCoeffds(const doublereal dTds, const doublereal* const dXds,
                                  doublereal* dlnActCoeffds) const {
        err("getdlnActCoeffds");
    }

    //! Get the array of ln mole fraction derivatives of the log activity coefficients - diagonal component only
    /*!
     * This function is a virtual method.  For ideal mixtures
     * (unity activity coefficients), this can return zero.
     * Implementations should take the derivative of the
     * logarithm of the activity coefficient with respect to the
     * logarithm of the mole fraction variable
     * that represents the standard state.
     * This quantity is to be used in conjunction with derivatives of
     * that mole fraction variable when the derivative of the chemical
     * potential is taken.
     *
     *  units = dimensionless
     *
     * @param dlnActCoeffdlnX_diag    Output vector of derivatives of the
     *                                log Activity Coefficients wrt the mole fractions. length = m_kk
     */
    virtual void getdlnActCoeffdlnX_diag(doublereal* dlnActCoeffdlnX_diag) const {
        err("getdlnActCoeffdlnX_diag");
    }

    //! Get the array of log species mole number derivatives of the log activity coefficients
    /*!
     *  This function is a virtual method.
     *  For ideal mixtures  (unity activity coefficients), this can return zero.
     *  Implementations should take the derivative of the
     *  logarithm of the activity coefficient with respect to the
     *  logarithm of the concentration-like variable (i.e. moles)
     *  that represents the standard state.
     *  This quantity is to be used in conjunction with derivatives of
     *  that species mole number variable when the derivative of the chemical
     *  potential is taken.
     *
     *  units = dimensionless
     *
     * @param dlnActCoeffdlnN_diag    Output vector of derivatives of the
     *                                log Activity Coefficients. length = m_kk
     */
    virtual void getdlnActCoeffdlnN_diag(doublereal* dlnActCoeffdlnN_diag) const {
        err("getdlnActCoeffdlnN_diag");
    }

    //! Get the array of derivatives of the log activity coefficients with respect to the log of the species mole numbers
    /*!
     * Implementations should take the derivative of the logarithm of the activity coefficient with respect to a
     * species log mole number (with all other species mole numbers held constant). The default treatment in the
     * %ThermoPhase object is to set this vector to zero.
     *
     *  units = 1 / kmol
     *
     *  dlnActCoeffdlnN[ ld * k  + m]  will contain the derivative of log act_coeff for the <I>m</I><SUP>th</SUP>
     *                               species with respect to the number of moles of the <I>k</I><SUP>th</SUP> species.
     *
     * \f[
     *        \frac{d \ln(\gamma_m) }{d \ln( n_k ) }\Bigg|_{n_i}
     * \f]
     *
     * @param ld               Number of rows in the matrix
     * @param dlnActCoeffdlnN    Output vector of derivatives of the
     *                           log Activity Coefficients. length = m_kk * m_kk
     */
    virtual void getdlnActCoeffdlnN(const size_t ld, doublereal* const dlnActCoeffdlnN);

    virtual void getdlnActCoeffdlnN_numderiv(const size_t ld, doublereal* const dlnActCoeffdlnN);

    //! @}
    //! @name Printing
    //! @{

    //! returns a summary of the state of the phase as a string
    /*!
     * @param show_thermo If true, extra information is printed out
     *                    about the thermodynamic state of the system.
     */
    virtual std::string report(bool show_thermo = true) const;

    //! returns a summary of the state of the phase to a comma separated file.
    //! To customize the data included in the report, derived classes should
    //! override the getCsvReportData method.
    /*!
     * @param csvFile     ofstream file to print comma separated data for
     *                    the phase
     */
    virtual void reportCSV(std::ofstream& csvFile) const;

    //@}

protected:

    //! Fills `names` and `data` with the column names and species thermo
    //! properties to be included in the output of the reportCSV method.
    virtual void getCsvReportData(std::vector<std::string>& names,
                                  std::vector<vector_fp>& data) const;

    //! Pointer to the calculation manager for species
    //! reference-state thermodynamic properties
    /*!
     *   This class is called when the reference-state thermodynamic properties
     *   of all the species in the phase needs to be evaluated.
     */
    SpeciesThermo* m_spthermo;

    //! Vector of pointers to the species databases.
    /*!
     * This is used to access data needed to
     * construct the transport manager and other properties
     * later in the initialization process.
     * We create a copy of the XML_Node data read in here. Therefore, we own this
     * data.
     */
    std::vector<const XML_Node*> m_speciesData;

    //! Stored value of the electric potential for this phase
    /*!
     * Units are Volts
     */
    doublereal m_phi;

    /// Vector of element potentials.
    /// Length equal to number of elements.
    vector_fp m_lambdaRRT;

    //! Boolean indicating whether there is a valid set of saved element potentials
    //! for this phase
    bool m_hasElementPotentials;

    //! Boolean indicating whether a charge neutrality condition is a necessity
    /*!
     * Note, the charge neutrality condition is not a necessity for ideal gas phases. There may
     * be a net charge in those phases, because the NASA polynomials for ionized species
     * in Ideal gases take this condition into account.
     * However, liquid phases usually require charge neutrality in order for their derived
     * thermodynamics to be valid.
     */
    bool m_chargeNeutralityNecessary;

    //! Contains the standard state convention
    int m_ssConvention;

    //! Reference Mole Fraction Composition
    /*!
     *  Occasionally, the need arises to find a safe mole fraction vector to initialize
     *  the object to. This contains such a vector.
     *  The algorithm will pick up the mole fraction vector that is applied from
     *  the state xml file in the input file
     */
    std::vector<doublereal> xMol_Ref;

private:

    //! Error function that gets called for unhandled cases
    /*!
     * @param msg String containing the message.
     */
    doublereal err(const std::string& msg) const;

};

//! typedef for the ThermoPhase class
typedef ThermoPhase thermo_t;

}

#endif