3.6.1. REACTIONS Line Options

On the same line as the REACTIONS word, you may specify units of the Arrhenius rate coefficients (Equation 3–5 of the Chemkin Theory Manual ) followed by the word CAL/MOLE, KCAL/MOLE, JOULES/MOLE, KJOULES/MOLE, KELVINS, or EVOLTS for E _i, and/or MOLES or MOLECULES for A _i. If MOLECULES is specified, then the units for A _i are cm, molecules, sec, and K.

Note: If units are not specified, A _i and E _i must be in cm, mole, sec, K, and cal/mole, respectively. Note that T is always in Kelvin. Ansys Chemkin uses the thermal calorie, 4.184 Joules.

Table 3.4: Alphabetical Listing of REACTIONS-line Options for Gas-phase Kinetics Data

Keyword	Definition
CAL/[MOLE]	Reiterates the default units for all gas-phase reactions that follow the `REACTIONS` header line for parameters with energy units such as E _i. Notes - Default units for E _i are cal/mole.
EVOL[TS]	Supersedes the default units for all gas-phase reactions which follow the `REACTIONS` header line for parameters with energy units such as E _i. Notes - Default units for E _i are cal/mole.
JOUL[ES/MOLE]	Supersedes the default units for all gas-phase reactions which follow the `REACTIONS` header line for parameters with energy units such as E _i. Notes - Default units for E _i are cal/mole.
KCAL[/MOLE]	Supersedes the default units for all gas-phase reactions which follow the `REACTIONS` header line for parameters with energy units such as E _i. Notes - Default units for E _i are cal/mole.
KELV[INS]	Supersedes the default units for all gas-phase reactions which follow the `REACTIONS` header line for parameters with energy units such as E _i. Notes - Default units for E _i are cal/mole.
KJOU[LES/MOLE]	Supersedes the default units for all gas-phase reactions which follow the `REACTIONS` header line for parameters with energy units such as E _i. Notes - Default units for E _i are cal/mole.
MOLEC[ULES]	Supersedes the default units for all gas-phase reactions which follow the `REACTIONS` header line for pre-exponential factors A _i. Notes - Default units for A _i are cgs (cm, sec, K, mole), the exact units depending on the order of the reaction.
MAXSP	Increases the maximum number of reactants or products allowed in a reaction. The number given by this keyword must be greater than the default limit of 6. For example, `REACTIONS MAXSP=11`. Notes -This keyword is available to both the gas-phase and surface reaction mechanism.
MOLE[S]	Supersedes the default units for all gas-phase reactions which follow the `REACTIONS` header line for pre-exponential factors A _i. Notes - Default units for A _i are cgs (cm, sec, K, mole), the exact units depending on the order of the reaction.
USRPROD	Indicates that the user will provide a user-written rate routine that will supply all of the species net rates of production, overriding any other reaction input in the Gas-phase Kinetics input file. The net rate-of-production for all species will be obtained by calling the user-supplied subroutine, `CKUPROD`. An optional slash(/)-delimited integer parameter allows the user to select from more than one type of rate formulation. Wherever the species production rates are required, they will be obtained by calling the user-written subroutine called CKUPROD. A template of `CKUPROD` is provided in the Ansys Chemkin installation, in the file cklib_user_routines.f located in the directory user_subroutines. Information about how to compile and link user routines into Chemkin is included in Chemkin Application Programming Interface Manual. Notes - `USRPROD` cannot be used in conjunction with USRPROG (entered after a particular reaction).

Note: This API does not support user-written programming, so you are cautioned to use the CKUPROD user-routine feature at your own risk. Also, there are some features in Ansys Chemkin that will be incompatible with the global replacement of species rates of production, such as sensitivity analysis and rate-of-production analysis. Such features will return zero values when user-rate programming is encountered.