rmgpy.kinetics.ThirdBody¶

class rmgpy.kinetics.ThirdBody(arrheniusLow=None, Tmin=None, Tmax=None, Pmin=None, Pmax=None, efficiencies=None, comment='')

A kinetic model of a phenomenological rate coefficient $$k(T, P)$$ using third-body kinetics. The attributes are:

Attribute Description
arrheniusLow The Arrhenius kinetics at the low-pressure limit
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
efficiencies A dict associating chemical species with associated efficiencies
comment Information about the model (e.g. its source)

Third-body kinetics simply introduce an inert third body to the rate expression:

$k(T,P) = k_0(T) [\mathrm{M}]$

Above, $$[\mathrm{M}] \approx P/RT$$ is the concentration of the bath gas. This formulation is equivalent to stating that the kinetics are always in the low-pressure limit.

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.

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.

arrheniusLow

arrheniusLow – rmgpy.kinetics.arrhenius.Arrhenius

changeRate(self, double factor)

Changes kinetics rate by a multiple factor.

comment

comment – str

discrepancy(self, KineticsModel otherKinetics) → double

Returns some measure of the discrepancy based on two different reaction models.

efficiencies

efficiencies – dict

getCanteraEfficiencies(self, speciesList)

Returns a dictionary containing the collider efficiencies for this PDepKineticsModel object suitable for setting the efficiencies in the following cantera reaction objects: ThreeBodyReaction, FalloffReaction,ChemicallyActivatedReaction

getEffectiveColliderEfficiencies(self, list species) → ndarray

Return the effective collider efficiencies for all species in the form of a numpy array. This function helps assist rapid effective pressure calculations in the solver.

getEffectivePressure(self, double P, list species, ndarray fractions) → double

Return the effective pressure in Pa for a system at a given pressure P in Pa composed of the given list of species (Species or Molecule objects) with the given fractions.

getRateCoefficient(self, double T, double P=0.0) → double

Return the value of the rate coefficient $$k(T)$$ in units of m^3, mol, and s at the specified temperature T in K and pressure P in Pa. If you wish to consider collision efficiencies, then you should first use getEffectivePressure() to compute the effective pressure, and pass that value as the pressure to this method.

highPlimit

highPlimit – rmgpy.kinetics.model.KineticsModel

isIdenticalTo(self, KineticsModel otherKinetics) → bool

Checks to see if kinetics matches that of other kinetics and returns True if coeffs, kunits, Tmin,

isPressureDependent(self) → bool

Return True since all objects derived from PDepKineticsModel represent pressure-dependent kinetics.

isPressureValid(self, double P) → bool

Return True if the pressure P in Pa is within the valid pressure range of the kinetic data, or False if not. If the minimum and maximum pressure are not defined, True is returned.

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, or False if not. If the minimum and maximum temperature are not defined, True is returned.

setCanteraKinetics(self, ctReaction, speciesList)

Sets the kinetics and efficiencies for a cantera ThreeBodyReaction object

toHTML(self)

Return an HTML rendering.