rmgpy.kinetics.Arrhenius¶

class
rmgpy.kinetics.
Arrhenius
(A=None, n=0.0, Ea=None, T0=(1.0, 'K'), Tmin=None, Tmax=None, Pmin=None, Pmax=None, comment='')¶ A kinetics model based on the (modified) Arrhenius equation. The attributes are:
Attribute Description A The preexponential factor T0 The reference temperature n The temperature exponent Ea The activation energy Tmin The minimum temperature at which the model is valid, or zero if unknown or undefined Tmax The maximum temperature at which the model is valid, or zero if unknown or undefined Pmin The minimum pressure at which the model is valid, or zero if unknown or undefined Pmax The maximum pressure at which the model is valid, or zero if unknown or undefined comment Information about the model (e.g. its source) The Arrhenius equation, given below, accurately reproduces the kinetics of many reaction families:
\[k(T) = A \left( \frac{T}{T_0} \right)^n \exp \left( \frac{E_\mathrm{a}}{RT} \right)\]Above, \(A\) is the preexponential factor, \(T_0\) is the reference temperature, \(n\) is the temperature exponent, and \(E_\mathrm{a}\) is the activation energy.

A
¶ The preexponential factor.

Ea
¶ The activation energy.

Pmax
¶ The maximum pressure at which the model is valid, or
None
if not defined.

Pmin
¶ The minimum pressure at which the model is valid, or
None
if not defined.

T0
¶ The reference temperature.

Tmax
¶ The maximum temperature at which the model is valid, or
None
if not defined.

Tmin
¶ The minimum temperature at which the model is valid, or
None
if not defined.

changeRate
(self, double factor)¶ Changes A factor in Arrhenius expression by multiplying it by a
factor
.

changeT0
(self, double T0)¶ Changes the reference temperature used in the exponent to T0 in K, and adjusts the preexponential factor accordingly.

comment
¶ comment – str

discrepancy
(self, KineticsModel otherKinetics) → double¶ Returns some measure of the discrepancy based on two different reaction models.

fitToData
(self, ndarray Tlist, ndarray klist, str kunits, double T0=1, ndarray weights=None, bool threeParams=True)¶ Fit the Arrhenius parameters to a set of rate coefficient data klist in units of kunits corresponding to a set of temperatures Tlist in K. A linear leastsquares fit is used, which guarantees that the resulting parameters provide the best possible approximation to the data.

getRateCoefficient
(self, double T, double P=0.0) → double¶ Return the rate coefficient in the appropriate combination of m^3, mol, and s at temperature T in K.

isIdenticalTo
(self, KineticsModel otherKinetics) → bool¶ Returns
True
if kinetics matches that of another kinetics model. Must match temperature and pressure range of kinetics model, as well as parameters: A, n, Ea, T0. (Shouldn’t have pressure range if it’s Arrhenius.) Otherwise returnsFalse
.

isPressureDependent
(self) → bool¶ Return
False
since, by default, all objects derived from KineticsModel represent pressureindependent kinetics.

isSimilarTo
(self, KineticsModel otherKinetics) → bool¶ Returns
True
if rates of reaction at temperatures 500,1000,1500,2000 K and 1 and 10 bar are within +/ .5 for log(k), in other words, within a factor of 3.

isTemperatureValid
(self, double T) → bool¶ Return
True
if the temperature T in K is within the valid temperature range of the kinetic data, orFalse
if not. If the minimum and maximum temperature are not defined,True
is returned.

n
¶ The temperature exponent.

setCanteraKinetics
(self, ctReaction, speciesList)¶ Passes in a cantera ElementaryReaction() object and sets its rate to a Cantera Arrhenius() object.

toArrheniusEP
(self, double alpha=0.0, double dHrxn=0.0) → ArrheniusEP¶ Converts an Arrhenius object to ArrheniusEP
If setting alpha, you need to also input dHrxn, which must be given in J/mol (and vise versa).

toCanteraKinetics
(self)¶ Converts the Arrhenius object to a cantera Arrhenius object
Arrhenius(A,b,E) where A is in units of m^3/kmol/s, b is dimensionless, and E is in J/kmol

toHTML
(self)¶ Return an HTML rendering.
