binaryRecombination

binaryRecombination

Works with VSimPD license.

kind of MonteCarlo interaction that models the recombination of an electron with an ionized atom.

The builtIn recombination rate coefficient in Vorpal is:

\[C_i = \alpha_r + \alpha_d\]

with:

\[\alpha_r = A_{rad}(T/10^4)^{-X_{rad}}\]

\[\alpha_d = A_{di} T^{-3/2} \exp(-T_0/T) \times \left[ 1 +B_{di}\exp \left(-T_1/T \right) \right]\]

where \(T=0.5mv^2\) is the temperature in K, with \(v\) the relative velocity of the two particles interacting. The coefficients \(A_{rad}\), \(X_{rad}\), \(A_{di}\), \(B_{di}\), \(T_0\) and \(T_1\) are calculated in [SVS82], and must be specified in the input file.

Note

This feature replaces the recombination feature, which was previously implemented in the Vorpal collisions.

binaryRecombination Parameters

crossSection (string)

Cross section to be used in the interaction. Possible values are builtIn or functionDefined. See below for required parameters for each choice.

electrons (string)

Name of the species describing the electrons recombining with the ionized atom.

inSpecies (string)

Name of the species describing the ionized atom.

outSpecies (string)

Name of the recombination product species.

intElecMass (real, optional)

Mass of the interacting electron. Default value is the mass specified in the electrons species block.

builtIn Parameters

Please see Types of collisions for the available builtIn gases.

The builtIn option is based on the data from Shull and Van Steenberg [SVS82].

If the builtIn cross section type is used the following parameters must be set:

Arad (real)

Coefficient used in the calculation of the recombination rate. This parameter can be found in tables in the paper by [SVS82].

Xrad (real)

Coefficient used in the calculation of the recombination rate. This parameter can be found in tables in the paper by [SVS82].

Adi (real)

Coefficient used in the calculation of the recombination rate. This parameter can be found in tables in the paper by [SVS82].

Bdi (real)

Coefficient used in the calculation of the recombination rate. This parameter can be found in tables in the paper by [SVS82].

T0 (real)

Coefficient used in the calculation of the recombination rate. This parameter can be found in tables in the paper by [SVS82].

T1 (real)

Coefficient used in the calculation of the recombination rate. This parameter can be found in tables in the paper by [SVS82].

functionDefined Parameters

If the functionDefined cross section type is used, the following parameters must be set:

OAFunc (block, required)

An OAFunc block of name crossSectionFunc must be used inside the Interaction block. The OAFunc block allows the user to define its own cross section for the interaction, either through a two-column data file or through an expression. The kinds of OAFunc available for this interaction are interpolatedFromFile, LXcatFile, or expression. The OAFunc must return the value of the cross section in m².

Please see OAFunc Block for more information on the OAFunc block.

crossSectionVariable (string, optional, default = velocity)

Used in the case when an OAFunc function is given for the cross section to specify whether the parameter of the function is either the:

• Relative collision velocity magnitude of the incident particle in m^-1: crossSectionVariable = velocity

• Kinetic energy of the incident particle in eV: crossSectionVariable = energy

Example binaryRecombination Block

<Interaction binary>
  kind = binaryRecombination
  electrons = electrons
  intElecMass = 9.1093896999999993e-31
  inSpecies = oxygen1
  outSpecies = oxygen0
  crossSection = builtIn
  # use parameters for crossSection calculation
  Arad = 1.24e-6
  Xrad = 6.78e-1
  Adi = 4440.0
  Bdi = 9.25e-2
  T0 = 1.75e5
  T1 = 1.45e5
</Interaction>