Electron collision plasma reaction rate type. More...

#include <ElectronCollisionPlasmaRate.h>

Inheritance diagram for ElectronCollisionPlasmaRate:

Detailed Description

Electron collision plasma reaction rate type.

The electron collision plasma reaction rate uses the electron collision data and the electron energy distribution to calculate the reaction rate. Hagelaar and Pitchford [14] define the reaction rate coefficient (Eqn. 63) as,

\[ k = \gamma \int_0^{\infty} \epsilon \sigma F_0 d\epsilon, \]

where \( \gamma = \sqrt{2/m_e} \) (Eqn.4 in [15]), \( m_e \) [kg] is the electron mass, \( \epsilon \) [J] is the electron energy, \( \sigma \) [m²] is the reaction collision cross section, \( F_0 \) [ \( \mbox{J}^{-3/2} \)] is the normalized electron energy distribution function, and \( k \) has the unit of [m³/s]. The collision process is treated as a bimolecular reaction and should have units of [m³/kmol/s]. Therefore the forward reaction coefficient becomes,

\[ k_f = \gamma N_A \int_0^{\infty} \epsilon \sigma F_0 d\epsilon, \]

where \( N_A \) [1/kmol] is the Avogadro's number. Since the unit of the electron energy downloaded from LXCat is in [eV], the elementary charge, e, can be taken out of the integral and combine with \( \gamma \) to get,

\[ k_f = \sqrt{\frac{2e}{m_e}} N_A \int_0^{\infty} \epsilon_V \sigma F_{0,V} d\epsilon_V. \]

In addition to the forward reaction coefficient, the reverse (super-elastic) reaction coefficient can be written as,

\[ k_r = \sqrt{\frac{2e}{m_e}} N_A \int_0^{\infty} \epsilon_V \sigma_{super} F_{0,V} d\epsilon_V, \]

where \( \sigma_{super} \) is the super-elastic cross section, defined by the principle of detailed balancing as:

\[ \sigma_{super}(\epsilon) = \frac{\epsilon + U}{\epsilon} \sigma(\epsilon + U), \]

where \( U \) is the threshold energy [eV], equal to the first energy level of the cross section (m_energyLevels).

Since: New in Cantera 3.1.

Definition at line 101 of file ElectronCollisionPlasmaRate.h.

Public Member Functions
	ElectronCollisionPlasmaRate (const AnyMap &node, const UnitStack &rate_units={})
	Constructor from YAML input for ElectronCollisionPlasmaRate.

virtual void	setParameters (const AnyMap &node, const UnitStack &units) override
	Set parameters.

virtual void	getParameters (AnyMap &node) const override
	Get parameters.

unique_ptr< MultiRateBase >	newMultiRate () const override
	Create a rate evaluator for reactions of a particular derived type.

virtual const std::string	type () const override
	String identifying reaction rate specialization.

virtual void	setContext (const Reaction &rxn, const Kinetics &kin) override
	Set context of reaction rate evaluation.

double	evalFromStruct (const ElectronCollisionPlasmaData &shared_data)
	Evaluate reaction rate.

void	modifyRateConstants (const ElectronCollisionPlasmaData &shared_data, double &kf, double &kr)
	Calculate the reverse rate coefficient for super-elastic collisions.

double	ddTScaledFromStruct (const ElectronCollisionPlasmaData &shared_data) const
	Evaluate derivative of reaction rate with respect to temperature divided by reaction rate.

const string &	kind () const
	The kind of the process which will be one of the following:

const string &	target () const
	Get the target species of the electron collision process.

const string &	product () const
	Get the product of the electron collision process.

double	threshold () const
	Get the energy threshold of electron collision [eV].

const vector< double > &	energyLevels () const
	The value of m_energyLevels [eV].

const vector< double > &	crossSections () const
	The value of m_crossSections [m2].

const vector< double > &	crossSectionInterpolated () const
	The value of m_crossSectionsInterpolated [m2].

void	updateInterpolatedCrossSection (const vector< double > &)
	Update the value of m_crossSectionsInterpolated [m2].

Public Member Functions inherited from ReactionRate
	ReactionRate (const ReactionRate &other)

ReactionRate &	operator= (const ReactionRate &other)

virtual unique_ptr< MultiRateBase >	newMultiRate () const
	Create a rate evaluator for reactions of a particular derived type.

virtual const string	type () const =0
	String identifying reaction rate specialization.

virtual const string	subType () const
	String identifying sub-type of reaction rate specialization.

virtual void	setParameters (const AnyMap &node, const UnitStack &units)
	Set parameters.

AnyMap	parameters () const
	Return the parameters such that an identical Reaction could be reconstructed using the newReaction() function.

const Units &	conversionUnits () const
	Get the units for converting the leading term in the reaction rate expression.

virtual void	setRateUnits (const UnitStack &rate_units)
	Set the units of the reaction rate expression.

virtual void	check (const string &equation)
	Check basic syntax and settings of reaction rate expression.

virtual void	validate (const string &equation, const Kinetics &kin)
	Validate the reaction rate expression.

size_t	rateIndex () const
	Reaction rate index within kinetics evaluator.

void	setRateIndex (size_t idx)
	Set reaction rate index within kinetics evaluator.

virtual void	setContext (const Reaction &rxn, const Kinetics &kin)
	Set context of reaction rate evaluation.

double	eval (double T)
	Evaluate reaction rate based on temperature.

double	eval (double T, double extra)
	Evaluate reaction rate based on temperature and an extra parameter.

double	eval (double T, const vector< double > &extra)
	Evaluate reaction rate based on temperature and an extra vector parameter.

bool	valid () const
	Get flag indicating whether reaction rate is set up correctly.

bool	compositionDependent ()
	Boolean indicating whether rate has compositional dependence.

void	setCompositionDependence (bool comp_dep)
	Set rate compositional dependence.

Private Attributes
string	m_kind
	The name of the kind of electron collision.

string	m_target
	The name of the target of electron collision.

string	m_product
	The product of electron collision.

double	m_threshold
	The energy threshold of electron collision.

vector< double >	m_energyLevels
	electron energy levels [eV]

int	m_levelNumber = -3
	Counter used to indicate when m_energyLevels needs to be synced with the phase.

int	m_levelNumberSuperelastic = -2
	Counter used to indicate when m_crossSectionsOffset needs to be synced with the phase.

vector< double >	m_crossSections
	collision cross sections [m2] at m_energyLevels

vector< double >	m_crossSectionsInterpolated
	collision cross sections [m2] after interpolation

Eigen::ArrayXd	m_crossSectionsOffset
	collision cross section [m2] interpolated on m_energyLevels offset by the threshold energy (the first energy level).

Additional Inherited Members
virtual void	getParameters (AnyMap &node) const
	Get parameters.

Protected Attributes inherited from ReactionRate
AnyMap	m_input
	Input data used for specific models.

size_t	m_rate_index = npos
	Index of reaction rate within kinetics evaluator.

bool	m_valid = false
	Flag indicating whether reaction rate is set up correctly.

bool	m_composition_dependent_rate = false
	Flag indicating composition dependent rate.

Units	m_conversion_units {0.}
	Units of the leading term in the reaction rate expression.

Constructor & Destructor Documentation

◆ ElectronCollisionPlasmaRate()

ElectronCollisionPlasmaRate	(	const AnyMap &	node,
		const UnitStack &	rate_units = `{}`
	)

inline

Constructor from YAML input for ElectronCollisionPlasmaRate.

This constructor is used to initialize an electron collision plasma rate from an input YAML file. It extracts the energy levels, cross-sections, and reaction metadata used in the rate coefficient calculation.

Parameters

node	The AnyMap node containing rate fields from YAML
rate_units	Units used for interpreting the rate fields

Definition at line 114 of file ElectronCollisionPlasmaRate.h.

Member Function Documentation

◆ setParameters()

void setParameters	(	const AnyMap &	node,
		const UnitStack &	units
	)

overridevirtual

Set parameters.

Parameters

node	AnyMap object containing reaction rate specification
units	unit definitions specific to rate information

Reimplemented from ReactionRate.

Definition at line 48 of file ElectronCollisionPlasmaRate.cpp.

◆ getParameters()

void getParameters ( AnyMap & node ) const

overridevirtual

Get parameters.

Parameters

node	AnyMap containing rate information Store the parameters of a ReactionRate needed to reconstruct an identical object. Does not include user-defined fields available in the m_input map.

Reimplemented from ReactionRate.

Definition at line 70 of file ElectronCollisionPlasmaRate.cpp.

◆ newMultiRate()

unique_ptr< MultiRateBase > newMultiRate ( ) const

inlineoverridevirtual

Create a rate evaluator for reactions of a particular derived type.

Derived classes usually implement this as:

unique_ptr<MultiRateBase> newMultiRate() const override {

return make_unique<MultiRate<RateType, DataType>>();

Cantera::ElectronCollisionPlasmaRate::newMultiRate

unique_ptr< MultiRateBase > newMultiRate() const override

Create a rate evaluator for reactions of a particular derived type.

Definition ElectronCollisionPlasmaRate.h:124

where RateType is the derived class name and DataType is the corresponding container for parameters needed to evaluate reactions of that type.

Reimplemented from ReactionRate.

Definition at line 124 of file ElectronCollisionPlasmaRate.h.

◆ type()

virtual const std::string type ( ) const

inlineoverridevirtual

String identifying reaction rate specialization.

Implements ReactionRate.

Definition at line 129 of file ElectronCollisionPlasmaRate.h.

◆ setContext()

void setContext	(	const Reaction &	rxn,
		const Kinetics &	kin
	)

overridevirtual

Set context of reaction rate evaluation.

Parameters

rxn	Reaction object associated with rate
kin	Kinetics object used for rate evaluation This method allows for passing of information specific to the associated reaction when a ReactionRate object is added a MultiRate reaction evaluator.

Reimplemented from ReactionRate.

Definition at line 172 of file ElectronCollisionPlasmaRate.cpp.

◆ evalFromStruct()

double evalFromStruct ( const ElectronCollisionPlasmaData & shared_data )

Evaluate reaction rate.

Parameters

shared_data data shared by all reactions of a given type

Definition at line 89 of file ElectronCollisionPlasmaRate.cpp.

◆ modifyRateConstants()

void modifyRateConstants	(	const ElectronCollisionPlasmaData &	shared_data,
		double &	kf,
		double &	kr
	)

Calculate the reverse rate coefficient for super-elastic collisions.

Parameters

shared_data	Data structure with energy levels and EEDF
kf	Forward rate coefficient (input, unused)
kr	Reverse rate coefficient (output, modified)

Definition at line 127 of file ElectronCollisionPlasmaRate.cpp.

◆ ddTScaledFromStruct()

double ddTScaledFromStruct ( const ElectronCollisionPlasmaData & shared_data ) const

inline

Evaluate derivative of reaction rate with respect to temperature divided by reaction rate.

Parameters

shared_data data shared by all reactions of a given type

Definition at line 151 of file ElectronCollisionPlasmaRate.h.

◆ kind()

const string & kind ( ) const

inline

The kind of the process which will be one of the following:

"effective": A generic effective collision
"excitation": Electronic or vibrational excitation
"ionization": Electron-impact ionization
"attachment": Electron attachment
Since
New in Cantera 3.2.

Definition at line 161 of file ElectronCollisionPlasmaRate.h.

◆ target()

const string & target ( ) const

inline

Get the target species of the electron collision process.

This is the name of the neutral or ionic species that the electron interacts with

Since: New in Cantera 3.2.

Definition at line 168 of file ElectronCollisionPlasmaRate.h.

◆ product()

const string & product ( ) const

inline

Get the product of the electron collision process.

This is the name of the species or excited state of some species resulting from the process.

Note: this may not necessarily be represented by a distinct species in the mixture.

Since: New in Cantera 3.2.

Definition at line 178 of file ElectronCollisionPlasmaRate.h.

◆ threshold()

double threshold ( ) const

inline

Get the energy threshold of electron collision [eV].

By default, the threshold is set to the first non-zero energy value listed in the tabulated cross section data.

Note: This behavior may be subject to change. A more robust approach may use the energy corresponding to the first non-zero cross section value, rather than the first non-zero energy point in the data table.