3.6.3. Auxiliary Reaction Data

Auxiliary Reaction Data is entered in lines immediately following the Reaction Data for a specific reaction path. The format of an auxiliary information line is a character-string keyword followed by a slash-delimited (/) field, which begins and ends with a slash ( / ), and which contains an appropriate number of parameters (either integer, floating point, or "E" format).

These data or keywords are used to indicate different reaction-rate expressions, units, pressure-dependency, and other ways in which the reaction behavior may be modified. Table 3.8: Summary of the Rules for Auxiliary Reaction Data provides detailed information about the meaning and usage of each auxiliary keyword entry option for gas-phase reactions. Also, Figure 3.5: Examples of Auxiliary Reaction Data provides some additional examples of reaction data.

Table 3.7: Alphabetical Listing of Gas-phase Reaction Auxiliary Keywords

Keyword	Definition
<SpeciesName>	Neutral Third Body Efficiency - If a reaction contains M as a reactant and/or product, auxiliary information lines may follow the reaction line to specify enhanced third-body efficiencies of certain species (that is, a _ki, Equation 3–19 of the Chemkin Theory Manual ). To define an enhanced third body efficiency, the keyword is the species name of the third body, and its one parameter is its enhanced efficiency factor. A species that acts as an enhanced third body must be declared as a species. Examples of third body efficiencies are shown in the first three reactions in Figure 3.5: Examples of Auxiliary Reaction Data .
	Parameters	Optional/Reqd.	Units	Examples
	Species name	Required	--	CO/1.87/
	Stoichiometric coefficient	Required	--	CO/1.87/
	Reaction Example	`REACTIONS CAL/MOLE` `HCO+M=H+CO+M 0.250E+15 0.000 16802.000 ! Warnatz` `CO/1.87/ H2/1.87 CH4/2.81/ CO2/3./ H2O/5./`
CHEB	Chebyshev Polynomial Rate Expressions - Supersedes the default reaction rate expression by a Chebyshev polynomial evaluation (see Equation 3–43 of the Chemkin Theory Manual ). `CHEB` must be followed by (slash delimited) parameters; for the first `CHEB`, the first value is N, the number of basis functions along the temperature axis; the second is M, the number of basis functions along the pressure axis; and the remainder are the N x M coefficients anm from Equation 3–41 in the order of a ₁₁, a ₁₂, ..., a ₁ M, a ₂₁, a nm, in this or additional `CHEB` declarations.
	Parameters	Optional/Reqd.	Units	Examples
	Number of temperature functions N	Required	--	CHEB / 7 3 -4.1624 .9394 -.18563 12.438/
	Number of pressure functions M	Required	--	CHEB / 7 3 -4.1624 .9394 -.18563 12.438/
	Chebyshev coefficients a	Required	--	CHEB / 7 3 -4.1624 .9394 -.18563 12.438/
	Reaction Example	`C2H5 + O2 (+M) <=> C2H4E + HO2 (+M) 1.00E+00 .000 0. ! mecon 7/97` `CHEB/ 7 3 1.0216E+01 -1.1083E+00 -1.9807E-01 7.8325E-01/` `CHEB/ 1.1609E+00 1.1762E-01 -9.5707E-02 1.0928E-01 1.1551E-01/` `CHEB/ -8.0290E-02 -1.0978E-01 3.7074E-04 -1.4830E-02 -6.0589E-02/` `CHEB/ -2.8056E-02 6.9203E-03 -9.7259E-03 -1.3556E-02 7.6648E-03/` `CHEB/ 6.6865E-03 -8.8244E-04/`
	Notes	More than one set of CHEB data can appear for a given reaction, as many as required to input exactly N x M + 2 values. Pressure limits of the Chebyshev polynomial for this reaction may be provided by keyword PCHEB . Temperature limits of the Chebyshev polynomial for this reaction may be provided by keyword TCHEB .
COLLEFF	Efficiency of Collision Frequency Expression - If a reaction is bimolecular and the approximate collision diameters are known, then the collision frequency efficiency expression can be used to calculate the reaction rate constant. The Arrhenius parameters for the correction factor are specified on the reaction line. On the line following, the keyword `COLLEFF` is required to tell the interpreter the type of reaction. `A+B<=>Products a b c` `COLLEFF` In addition to the parameters for the correction factor a, b , and c, the diameters for each reacting species must be specified. Ansys Chemkin uses the Lennard-Jones diameter as an approximation for the spherical diameter of a species. The Lennard-Jones diameter is one of the inputs read by the Transport Pre-Processor that are specified as outlined in Transport Data Format .
COLLEFF	Reaction Example	`C6H6 + C6H6 => C12H10 + H2 0.02 0 0` `COLLEFF`
DUP	Duplicate Reactions - Two or more reactions can involve the same set of reactants and products, but proceed through distinctly different processes. In these cases, it may be appropriate to state a reaction mechanism that has two or more reactions that are the same, but have different rate parameters. However, duplicate reactions are normally considered errors by the Gas-phase Kinetics Pre-Processor. If the user requires duplication (for example, the same reactants and products with different Arrhenius parameters), the keyword `DUP` must follow the reaction line of each duplicate reaction, including the first occurrence of the reaction that is duplicated. For example, if the user wishes to specify different rate expressions for each of two identical reactions, there must be two occurrences of the `DUP` keyword, one following each of the reactions. No auxiliary parameters are required. Examples are shown in Figure 3.5: Examples of Auxiliary Reaction Data .
DUP	Reaction Example	`HO2+HO2=H2O2+O2 4.20E14 0.0 11982` `DUP` `HO2+HO2=H2O2+O2 1.3E11 0.0 -1629` `DUP`
EXCI	Energy Loss Parameter - Auxiliary data may be used to specify the energy loss per reaction event by specifying the keyword `EXCI`, followed by the value of the energy loss per event, in units of electron volts. This option overrides the calculation of energy loss from the change in enthalpy determined by the reaction description and the thermodynamic data of the reactants and products. The option is useful in describing electron-impact excitation reactions, for example, where the user does not wish to keep track of the excited-species density, but wants to include the energy loss to the electrons due to the excitation process. An example of the use of `EXCI` is given in Figure 3.5: Examples of Auxiliary Reaction Data . The `EXCI` keyword represents the parameter that is used to describe inelastic collisions in Equation 8–144 of the Chemkin Theory Manual for the electron balance in plasma simulations.
	Parameters	Optional/Reqd.	Units	Examples
	Energy loss per event	Required	electron- volts	TDEP/E/ EXCI/11.60/
	Reaction Example	`E + AR => AR + E 2.235E16 0.0 3.47E5` `TDEP/E/ EXCI/11.60/` `DUP`
FIT1	Supersedes the default reaction rate expression by the reaction rate described by Equation 3–50 of the Chemkin Theory Manual . `FIT1` must be followed by the four slash-delimited `FIT1` parameters, bni.
	Parameters	Optional/Reqd.	Units	Examples
	FIT1 parameters b ₁ - b ₄	Required	--	FIT1/33756 -1.695E8 1.08E13 0.0/
	Reaction Example	`E + O2 => O + O- 4.60E-11 0.0 0.` `TDEP/E/` `FIT1/33756 -1.695E8 1.08E13 0.0/`
FORD	Forward Reaction Order Parameter - Supersedes the forward reaction order for any species in the mechanism (with respect to species concentration), regardless of whether the species appears as a reactant or a product in the reaction. FORD is followed, in slash-delimited format, by the species name and the new reaction order. This option overrides the values of in Equation 3–4 of the Chemkin Theory Manual pertaining to the particular species named on the line. The reaction order for all other species maintain their default values.
	Parameters	Optional/Reqd.	Units	Examples
	Species name	Required	--	FORD /Pt(S) 1.0/
	Stoichiometric coefficient	Required	--	FORD /Pt(S) 1.0/
	Reaction Example	`JP10+14O2 => 10CO2 + 8H2O 6.454323E+13 0.0 29188.8` `FORD / JP10 1.153923 /` `FORD / O2 0.738210 /`
	Notes	Multiple occurrences of the FORD construct may appear on the auxiliary line.
HIGH	Defines the high-pressure limit for pressure-dependent chemically activated bimolecular reactions (see Equation 3–26 of the Chemkin Theory Manual ). `HIGH` must be followed by the three slash-delimited high-pressure limit Arrhenius parameters , , and , and the Arrhenius coefficients on the reaction line represent the low-pressure limit Arrhenius parameters , , and .
	Parameters	Optional/Reqd.	Units	Examples
	Pre-exponential factor	Required	Depends on reaction	HIGH /6.85E-12 6.53 -834./
	Temperature exponent	Required	--	HIGH /6.85E-12 6.53 -834./
	Activation energy	Required	cal/mole	HIGH /6.85E-12 6.53 -834./
	Reaction Example	`C2H5+O2(+M)= C2H4+HO2(+M) 1.41E7 1.09 -1975.` `HIGH/6.85E-12 6.53 -834./` `TROE/0.45 1.E-10 1.E10/` `H2/2/ CO/2/ CO2/3/ H2O/5/`
	Notes	Required when SRI or TROE is present Additional pressure-dependency parameters may be provided by keywords SRI or TROE. If no additional parameters, the Lindemann formulation is applied.
JAN	Optional Rate Fit Expressions - Supersedes the default reaction rate expression by a Janev-Langer reaction rate (see Equation 3–49 of the Chemkin Theory Manual ). `JAN` must be followed by the nine slash-delimited Janev-Langer rate parameters, b_ni.
	Parameters	Optional/Reqd.	Units	Examples
	Janev-Langer parameters b1 - b9	Required	eV	JAN / -19.73476 3.992702 -1.773436 0.5331949 -0.1 0.02 -0.002 8.E-5 -2.E-6/
	Reaction Example	`H* + E = H+ + 2E 1.0 0.0 0.0` `JAN / -19.73476 3.992702 -1.773436 0.5331949 -0.1 0.02 -0.002 8.E-5 -2.E-6/`
	Notes	If fewer than 9 parameters are required for the fit, the user must provide zeros for the remainder of the parameters. The Janev rate expression was originally designed for usage with plasmas, and the temperature unit is eV (that is, electron-volt). When the rate is calculated, the system temperature is first converted to eV. For temperatures in kelvin, it will be T/11595 in eV. Therefore the temperature needs to be in eV when fitting the `JAN` rate coefficients, while other reactions in the mechanism still use temperature in K.
LOW	Defines the low-pressure limit for pressure-dependent unimolecular fall-off reactions (see Equation 3–25 of the Chemkin Theory Manual ). `LOW` must be followed by the slash-delimited low-pressure limit Arrhenius parameters , , and , and the Arrhenius coefficients on the reaction line represent the three high-pressure limit Arrhenius parameters , , and .
	Parameters	Optional/Reqd.	Units	Examples
	Pre-exponential factor	Required	depends on reaction	LOW /1.73E69 -15.07 60491./
	Temperature exponent	Required	--	LOW /1.73E69 -15.07 60491./
	Activation energy	Required	cal/mole	LOW /1.73E69 -15.07 60491./
	Reaction Example	`O+CO(+M)<=>CO2(+M) 1.800E+10 .000 2385.00` `LOW/ 6.020E+14 .000 3000.00/`
	Notes	Required when SRI or TROE is present Supplemental pressure-dependency parameters may be provided by keywords SRI or TROE. If no additional parameters, the Lindemann formulation is applied.
LT	Landau-Teller Reactions - Supersedes the default reaction rate expression by the Landau-Teller reaction rate (see Equation 3–47 of the Chemkin Theory Manual ). `LT` must be followed by the two slash-delimited Landau-Teller reaction rate parameters Bi and Ci.
	Parameters	Optional/Reqd.	Units	Examples
	Landau-Teller parameter B _i	Required	--	LT /-67 62.1/
	Landau-Teller parameter C _i	Required	--	LT /-67 62.1/
	Reaction Example	`H2(1)+H2O(000)=H2(0)+H2O(001) 2.89E15 0 0` `LT / -67 62.1/`
	Notes	If explicit REV parameters are given for the reaction, then explicit reverse Landau-Teller parameters must also be given by keyword RLT.
MOME	Plasma Momentum-Transfer Collision Frequency Options - Indicates that the reaction parameters describe the momentum-transfer collision frequency for electrons. This keyword requires no supplemental data, but changes the treatment of the reaction-rate coefficients. The option causes the reaction to be flagged as an electron momentum-transfer reaction, and assumes that the reaction rate constant is in units of cm³ /mole-s or cm³ /molecule-s, depending on the units specified in the `REACTIONS` statement. These reactions are treated as special cases when Gas-phase Kinetics subroutines evaluate reaction rates-of-progress, as described in Rates of Creation and Destruction of Species of the Chemkin Theory Manual .
	Reaction Example	`E + AR* => E + AR* 1.0502E-08 2.5929E-01 1.7464E+04` `TDEP/E/` `MOME`
	Notes	These options would generally not be used (or would be ignored) with any of the standard Ansys Chemkin reactor models; they are there for users who may be incorporating Chemkin into a multi-dimensional plasma simulation user program.
PCHEB	Supersedes the default pressure limits for a Chebyshev polynomial rate expression (see Equation 3–42 of the Chemkin Theory Manual ). `PCHEB` must be followed by the two slash-delimited values Pmin and Pmax.
	Parameters	Optional/Reqd.	Units	Examples
	Minimum pressure Pmin	Required	atm	PCHEB / 1.0 100.0/
	Maximum pressure Pmax	Required	atm	PCHEB / 1.0 100.0/
	Reaction Example	`C2H5+O2(+M)=C2H4E+HO2 (+M) 1.0 0.0 0.0` `LOW / 1.0 0.0 0.0 /` `PCHEB / 1.0 100.0/` `CHEB/ 7 3 10.216 -1.1083 -0.19807 0.78325/` `CHEB/ 1.1609 0.1.1762 -0.095707 0.10928 0.11551/` `CHEB/ -0.08029 -0.10978 3.7074E-04 -0.01483 -0.060589/` `CHEB/ -0.028056 6.9203E-03 -9.7259E-03 -0.013556 7.6648E-03/` `CHEB/ 6.6865E-03 -8.8244E-04/`
	Notes	The default Chebyshev polynomial pressure limits are P_min=0.001, P_max=100. Chebyshev polynomial parameters must be provided by use of keyword CHEB. Default Chebyshev polynomial temperature limits may be superseded by keyword TCHEB.
PLOG	Pressure Dependence Through Logarithmic Interpolation - Provides a general-purpose way of describing pressure-dependent reaction rates. Using the `PLOG` keywords, you can enter any number of sets of Arrhenius reaction-rate coefficients at different reactor pressures. The `PLOG` data will override the Arrhenius coefficients provided on the reaction line. The `PLOG` keyword must be followed by the slash-delimited values for the pressure at which the reaction rates are given and the three Arrhenius parameters, , , and , for that pressure. Multiple `PLOG` entries can be provided, but they must be included in ascending order of pressure. See the Ansys Chemkin Theory Manual, General Pressure Dependence Using Logarithmic Interpolation , General Pressure Dependence Using Logarithmic Interpolation .
	Parameters	Optional/Reqd.	Units	Examples
	Pressure		atm	PLOG /0.03947 2.9512E+09 1.28 13474./
	Pre-exponential factor		Depends on reaction	PLOG /0.03947 2.9512E+09 1.28 13474./
	Temperature exponent		--	PLOG /0.03947 2.9512E+09 1.28 13474./
	Activation energy		cal/mole	PLOG /0.03947 2.9512E+09 1.28 13474./
	Reaction Example	`H2CCCH+H=C3H2(S)+H2 2.9512E+09 1.28 13474.` `PLOG /0.03947 2.9512E+09 1.28 13474./` `PLOG /1. 1.0965E+10 1.13 13929./` `PLOG /10. 3.3113E+13 0.195 17579./` `PLOG /100. 3.3113E+13 0.195 17579./`
	Notes	There should not be more than one `PLOG` entry for the same pressure for a reaction. However, you can use the `DUPLICATE` option to have two reactions that are the same and that both use `PLOG` entries; in this case the resulting reaction-rates will be summed as is the usual case for `DUPLICATE` reactions.
REV	Reverse Rate Parameters - Supersedes the reverse rates that would normally be computed through the equilibrium constant, Equation 3–6 of the Chemkin Theory Manual . `REV` must be followed by the three slash-delimited Arrhenius coefficients (, , and ) to specify the reverse rate.
	Parameters	Optional/Reqd.	Units	Examples
	Pre-exponential factor		depends on reaction	REV / 6.61E-14 0.0 9561./
	Temperature exponent		--	REV / 6.61E-14 0.0 9561./
	Activation energy		cal/mole	REV / 6.61E-14 0.0 9561./
	Reaction Example	`C2F4 + M = CF2 + CF2 + M 1.126E-07 0. 27528.0` `REV / 9.381E-14 0. 31404.1 /`
RLT	Supersedes the default reverse reaction rate expression by the Landau-Teller reaction rate (see Equation 3–47 of the Chemkin Theory Manual ). `RLT` must be followed by the two slash-delimited Landau-Teller reaction rate parameters Bi and Ci.
	Parameters	Optional/Reqd.	Units	Examples
	Landau-Teller parameter B _i	Required	--	RLT /-67 62.1/
	Landau-Teller parameter C _i	Required	--	RLT /-67 62.1/
	Reaction Example	`H2(1)+H2O(000)=H2(0)+H2O(001) 2.89E15 0 0` `RLT / -67 62.1/`
	Notes	Required when the combination of LT and REV keywords is present. If explicit REV parameters are given for the reaction, then explicit reverse Landau-Teller parameters must also be given by keyword `RLT`.
RORD	Reverse Reaction Order Parameter - Supersedes the reverse reaction order for any species in the mechanism (with respect to species concentration), regardless of whether the species appears as a reactant or a product in the reaction. `RORD` must be followed by the slash-delimited species name and the new reaction order, and supersedes the values of in Equation 3–4 of the Chemkin Theory Manual pertaining to the particular species named on the line; the reaction order for all other species maintain their default values. Multiple occurrences of the `RORD` construct may appear on the auxiliary line.
	Parameters	Optional/Reqd.	Units	Examples
	Species name	Required	--	RORD /OH 2.0/
	Stoichiometric coefficient	Required	--	RORD /OH 2.0/
	Reaction Example	`H2+O2=2OH 0.170E+14 0.00 47780` `RORD /OH 2.0/`
	Notes	See also FORD.
SRI	Defines the SRI pressure-dependent reaction rate (see Equation 3–34 of the Chemkin Theory Manual ). `SRI` must be followed by either three, or five, slash-delimited parameters a, b, c, d, and e. The fourth and fifth parameters are optional and if omitted, they are by default d =1 and e =0.
	Parameters	Optional/Reqd.	Units	Examples
	SRI reaction rate parameters a - e	Required	--	SRI /0.45 797. 979. 1.0 0.0/
	Reaction Example	`CH3+H(+M) = CH4(+M) 6.0E16 -1.0 0` `LOW/8.0E26 -3.0 0/` `SRI/0.45 797.0 979.0/` `H2/2/ CO/2/ CO2/3/ H2O/5/`
	Notes	Additional `SRI` parameters are required, by use of keywords LOW or HIGH.
TCHEB	Supersedes the default temperature limits for a Chebyshev polynomial rate expression (see Equation 3–41 of the Chemkin Theory Manual ). `TCHEB` must be followed by the slash-delimited values, Tmin and Tmax.
	Parameters	Optional/Reqd.	Units	Examples
	Minimum temperature Tmin	Required	K	TCHEB / 300.0 2500./
	Maximum temperature Tmax	Required	K	TCHEB / 300.0 2500./
	Reaction Example	`C2H5+O2(+M)=C2H4E+HO2 (+M) 1.0 0.0 0.0` `LOW / 1.0 0.0 0.0 /` `TCHEB / 300. 2500./` `CHEB/ 7 3 10.216 -1.1083 -0.19807 0.78325/` `CHEB/ 1.1609 0.1.1762 -0.095707 0.10928 0.11551/` `CHEB/ -0.08029 -0.10978 3.7074E-04 -0.01483 -0.060589/` `CHEB/ -0.028056 6.9203E-03 -9.7259E-03 -0.013556 7.6648E-03/` `CHEB/ 6.6865E-03 -8.8244E-04/`
	Notes	The default Chebyshev polynomial temperature limits are Tmin=300, Tmax=2500. Required Chebyshev polynomial parameters must be provided by use of keyword CHEB. Supplemental Chebyshev polynomial pressure limits may be provided by use of keyword PCHEB.
TDEP	Species Temperature Dependence - Causes the reaction rate constant to be evaluated using the specified species temperature and the rate parameters given in the reaction data. In the case when there is more than one temperature defined in the system, the Application must call the Gas-phase Kinetics subroutine `CKKTFL` to indicate which temperature in the temperature array corresponds to each species. Examples of the `TDEP` input are shown in Figure 3.5: Examples of Auxiliary Reaction Data .
	Parameters	Optional/Reqd.	Units	Examples
	Species name	Required	--	TDEP/E/
	Keyword Usage	`E + CL2 => CL- + CL 5.8901E-09 -2.5619E-01 1.5834E+04` `TDEP/E/`
TROE	Defines the Troe pressure-dependent reaction rate (see Equation 3–33 of the Chemkin Theory Manual ). `TROE` must be followed by the slash-delimited 3 or 4 parameters α, T ^**, T ^, and T ^**; the fourth parameter is optional and if omitted, the last term in Equation 3–33 is not used.
	Parameters	Optional/Reqd.	Units	Examples
		Required	Depends on reaction	TROE /0.5336 629.2 2190. 626.5/
	T***	Required	K	TROE /0.5336 629.2 2190. 626.5/
	T*	Required	K	TROE /0.5336 629.2 2190. 626.5/
	T**	Optional	K	TROE /0.5336 629.2 2190. 626.5/
	Reaction Example	`C2H5+O2(+M)= C2H4+HO2(+M) 1.41E7 1.09 -1975.` `HIGH/6.85E-12 6.53 -834./` `TROE/0.45 1.E-10 1.E10/` `H2/2/ CO/2/ CO2/3/ H2O/5/`
	Notes	Other required `TROE` parameters must be provided by use of keywords LOW or HIGH.
UNITS	Reaction Units - Supersedes the current units for a particular reaction rate fit that may differ from the default units specified for other reaction expressions in the chemistry mechanism. `UNITS` must be followed by the slash-delimited character-string string, where string is one of the following: `EVOL[TS]`, `KELV[INS]`, `CAL/[MOLE]`, `KCAL[/MOLE]`, `JOUL[ES/MOLE]`, or `KJOU[LES/MOLE]` for parameters with energy units such as E _i, or `MOLES` or `MOLEC[ULES]` for pre-exponential factors A _i, where the letters in brackets are optional. The inclusion of `MOLEC[ULES]` would indicate that the reaction rate expression is in units of molecules/cm³ rather than mole/cm³. The `UNITS` auxiliary keyword allows only one string parameter, but the user can repeat the `UNITS` as many times as needed for a given reaction.
	Parameters	Optional/Reqd.	Units	Examples
	Reaction units character string	Required	--	UNITS /MOLECULES/
	Reaction Example	`CF3+ + E + #WSIO2(B) => #SIO2 + CF3 0.33 0.0 0.0` `BOHM !` `YIELD /0.01 20. 0.5 1.0/ UNITS/EVOLTS/`
	Notes	Default units for A _i are cgs (cm, sec, K, mole), the exact units depending on the order of the reaction. Default units for E _i are (cal/mole). If any of the units strings are given on the `REACTIONS` header line, it applies to all reactions, but may be superseded for a particular reaction by the auxiliary `UNITS` keyword Even if the default energy units are changed by giving the `UNITS` keyword, the temperature appearing in the Arrhenius expression of Equation 3–5 of the Chemkin Theory Manual is still in Kelvins.
USRPROG	Optional User Rate Subroutine CKUPROG `-` The net rate-of-progress for the reaction will be obtained by calling a user-supplied subroutine, CKUPROG. An optional slash(/)-delimited integer parameter allows the user to select from more than one type of rate formulation. Wherever the net reaction rate is required, it will be obtained by calling the user-written subroutine. A template of CKUPROG is provided in the Ansys Chemkin installation, in the file cklib_user_routines.f located in the directory user_routines. Information about how to compile and link user routines into Chemkin is included in Chemkin Application Programming Interface Manual.
	Parameters	Optional/Reqd.	Units	Examples
	Rate formulation type	Optional	--	USRPROG /1/
	Reaction Example	`H2+O2=>2OH 1.7E13 0.0 47780.` `USRPROG/1/`
	Notes	`USRPROG` applies only to irreversible reactions, and cannot be used in conjunction with `USRPROD` (entered on the `REACTIONS` header line).
XSMI	Flags a reaction as representing collision cross-section information for the determination of ion momentum-transfer collision frequencies in a plasma simulation. No auxiliary parameters are required. The evaluated rate-constant is assumed to be in cm², and is left as such when Gas-phase Kinetics subroutines evaluate rates of progress for other reactions. For more detail, see Rates of Creation and Destruction of Species of the Chemkin Theory Manual . Examples are given in Figure 3.5: Examples of Auxiliary Reaction Data .
	Reaction Example	`CL+ + CL => CL+ + CL 1.03E-13 -0.5 0.0` `TDEP/CL+/` `XSMI !momentum-transfer x-sec`
	Notes	These options would generally not be used (or would be ignored) with any of the standard Ansys Chemkin reactor models; they are there for users who may be incorporating Chemkin into a multi-dimensional plasma simulation user program.

Figure 3.5: Examples of Auxiliary Reaction Data

REACTIONS            CAL/MOLE   ! these are the default units for the reaction rates
HCO+M=H+CO+M             0.250E+15  0.000  16802.000                      !  Warnatz
CO/1.87/  H2/1.87  CH4/2.81/ CO2/3./  H2O/5./

H+C2H4(+M)=C2H5(+M)      0.221E+14  0.000  2066.000                        ! Michael
   LOW / 6.369E27  -2.76  -54.0 /                       !Lindemann fall-off reaction
   H2/2/  CO/2/  CO2/3/  H2O/5/                   ! enhanced third-body efficiencies

CH3+CH3(+M)=C2H6(+M)			9.03E16  -1.18  654.
   LOW / 3.18E41  -7.03  2762 /
   TROE / 0.6041  6927.  132. /          ! TROE fall-off reaction, with 3 parameters
   H2/2/  CO/2/  CO2/3/  H2O/5/                   ! enhanced third-body efficiencies

CH3+H(+M)=CH4(+M)			6.0E16  -1.0  0.0
   LOW / 8.0E26  -3.0  0.0/
   SRI  / 0.45  797.  979. /                                 ! SRI fall-off reaction
   H2/2/  CO/2/  CO2/3/  H2O/5/                   ! enhanced third-body efficiencies

CH3+CH3(+M)=H + C2H5(+M)			4.989E12 0.099   10600.0	! Stewart
   HIGH/ 3.80E-7  4.838   7710. /                    ! Chemically activated reaction
   SRI  / 1.641  4334  2725 /                              ! SRI pressure dependence

CH4+H=CH3+H2                1.25E14  0  1.190E4                          ! Westbrook
   REV / 4.80E12  0  1.143E4 /

! The following two reactions are acceptable duplicates:

H2+O2 = 2OH                    1.7E13   0   47780
   DUPLICATE
H2+O2 = 2OH                    1.0E13   0   47000.
   DUPLICATE

H2(1)+H2O(000)=H2(0)+H2O(001)  2.89E15  0  0
   LT / -67  62.1/                                          ! Landau-Teller reaction

! The following is a Chebyshev polynomial rate description

C2H5 + O2 (+M)       <=> C2H4E + HO2 (+M)  1.00E+00     .000       0.     ! Bozzelli
   TCHEB/ 300 2500/          PCHEB/1 100/
   CHEB/  7   3       1.0216E+01 -1.1083E+00 -1.9807E-01  7.8325E-01/
   CHEB/  1.1609E+00  1.1762E-01 -9.5707E-02  1.0928E-01  1.1551E-01/
   CHEB/ -8.0290E-02 -1.0978E-01  3.7074E-04 -1.4830E-02 -6.0589E-02/
   CHEB/ -2.8056E-02  6.9203E-03 -9.7259E-03 -1.3556E-02  7.6648E-03/
   CHEB/  6.6865E-03 -8.8244E-04/

! The following reactions allow plasma kinetics descriptions
E + E + AR+ <=> AR  +  E  1.414E+39   -4.500  0.00                 ! Mansbach & Keck
   TDEP/E/   REV/6.807E+31  -3.0 364218./           !electron temperature dependence

E + AR => AR + E          4.9E-7   0.162  8.7634E3
   TDEP/E/  MOME                              !Momentum-transfer collision frequency
   UNITS/KELVIN/

AR+ + AR => AR+ + AR      1.E-16   0.0   0.0                          !units of cm^2
   XSMI                               !Ion momentum-transfer collision cross-section

E + AR => AR + E          2.235E16  0.0  3.47E5
   TDEP/E/   EXCI/11.60/  ! metastable excitation reaction
   DUP
H2O+H = OH+H2             0.117E+10  1.30   3626 
   FORD /H2O 1.1/

END                                                            !END line is optional

3.6.3.1. Problems Having No Reactions

In some problems only information about the elements and species is needed (for example, chemical equilibrium computations). For these it is not necessary to include reaction data. The Gas-phase Kinetics Pre-processor will create the Linking File (for example, chem.asc), but it will not contain any reaction information. Therefore, no subroutines in the Gas-phase Kinetics Subroutine Library that deal with chemical reactions (for example, chemical production rates) may be used.

Table 3.8: Summary of the Rules for Auxiliary Reaction Data summarizes the rules for auxiliary reaction data.

Table 3.8: Summary of the Rules for Auxiliary Reaction Data

Rule	Description
1	Auxiliary information lines may follow reaction lines that contain an `M` to specify enhanced third-body efficiencies, a reversible reaction to specify the reverse rate parameters explicitly, or any reaction that specifies Landau-Teller parameters. Auxiliary information must follow any duplicate reactions as well as all reactions that indicate pressure-dependent behavior by (`+M`) (that is, provide fall-off parameters).
2	A species may have only one enhanced third body efficiency associated with it in any one reaction.
3	Only one radiation wavelength may be declared in a reaction.
4	The order in which the enhanced third body declarations are given is the order in which arrays of enhanced third body information are referenced in the subroutine package.
5	There cannot be more than ten enhanced third bodies in a reaction.
6	Keyword declarations may appear anywhere on the line, in any order.
7	Any number of keywords may appear on a line and more than one line may be used; however, a keyword and its parameter(s) must appear on the same line.
8	Keyword declarations that appear on the same line must be separated by at least one blank space.
9	Any blank spaces between a keyword and the first slash are ignored and any blanks between the slashes and parameter(s) are also ignored. However, no blank spaces are allowed within a keyword or a parameter.
10	All characters following an exclamation mark are comments.
11	In ion momentum-transfer collision cross-section reactions there must be exactly two reactant species, one of which must be an ion.
12	In electron momentum-transfer collision frequency reactions, there must be exactly two reactant species, one of which must be the electron.