rmgpy.thermo.
ThermoData
(Tdata=None, Cpdata=None, H298=None, S298=None, Cp0=None, CpInf=None, Tmin=None, Tmax=None, E0=None, comment='')¶A heat capacity model based on a set of discrete heat capacity data points. The attributes are:
Attribute | Description |
---|---|
Tdata | An array of temperatures at which the heat capacity is known |
Cpdata | An array of heat capacities at the given temperatures |
H298 | The standard enthalpy of formation at 298 K |
S298 | The standard entropy at 298 K |
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 |
E0 | The energy at zero Kelvin (including zero point energy) |
comment | Information about the model (e.g. its source) |
Cp0
¶The heat capacity at zero temperature.
CpInf
¶The heat capacity at infinite temperature.
Cpdata
¶An array of heat capacities at the given temperatures.
E0
¶The ground state energy (J/mol) at zero Kelvin, including zero point energy, or None
if not yet specified.
H298
¶The standard enthalpy of formation at 298 K.
S298
¶The standard entropy of formation at 298 K.
Tdata
¶An array of temperatures at which the heat capacity is known.
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.
comment
¶comment: str
discrepancy
(self, HeatCapacityModel other) → double¶Return some measure of how dissimilar self is from other.
The measure is arbitrary, but hopefully useful for sorting purposes. Discrepancy of 0 means they are identical
getEnthalpy
(self, double T) → double¶Return the enthalpy in J/mol at the specified temperature T in K.
getEntropy
(self, double T) → double¶Return the entropy in J/mol*K at the specified temperature T in K.
getFreeEnergy
(self, double T) → double¶Return the Gibbs free energy in J/mol at the specified temperature T in K.
getHeatCapacity
(self, double T) → double¶Return the constant-pressure heat capacity in J/mol*K at the specified temperature T in K.
isIdenticalTo
(self, HeatCapacityModel other) → bool¶Returns True
if self and other report very similar thermo values
for heat capacity, enthalpy, entropy, and free energy over a wide
range of temperatures, or False
otherwise.
isSimilarTo
(self, HeatCapacityModel other) → bool¶Returns True
if self and other report similar thermo values
for heat capacity, enthalpy, entropy, and free energy over a wide
range of temperatures, or False
otherwise.
isTemperatureValid
(self, double T) → bool¶Return True
if the temperature T in K is within the valid
temperature range of the thermodynamic data, or False
if not. If
the minimum and maximum temperature are not defined, True
is
returned.
toNASA
(self, double Tmin, double Tmax, double Tint, bool fixedTint=False, bool weighting=True, int continuity=3) → NASA¶Convert the object to a NASA
object. You must specify the
minimum and maximum temperatures of the fit Tmin and Tmax in K, as
well as the intermediate temperature Tint in K to use as the bridge
between the two fitted polynomials. The remaining parameters can be
used to modify the fitting algorithm used:
fixedTint - False
to allow Tint to vary in order to improve the fit, or True
to keep it fixed
weighting - True
to weight the fit by \(T^{-1}\) to emphasize good fit at lower temperatures, or False
to not use weighting
continuity - The number of continuity constraints to enforce at Tint:
- 0: no constraints on continuity of \(C_\mathrm{p}(T)\) at Tint
- 1: constrain \(C_\mathrm{p}(T)\) to be continous at Tint
- 2: constrain \(C_\mathrm{p}(T)\) and \(\frac{d C_\mathrm{p}}{dT}\) to be continuous at Tint
- 3: constrain \(C_\mathrm{p}(T)\), \(\frac{d C_\mathrm{p}}{dT}\), and \(\frac{d^2 C_\mathrm{p}}{dT^2}\) to be continuous at Tint
- 4: constrain \(C_\mathrm{p}(T)\), \(\frac{d C_\mathrm{p}}{dT}\), \(\frac{d^2 C_\mathrm{p}}{dT^2}\), and \(\frac{d^3 C_\mathrm{p}}{dT^3}\) to be continuous at Tint
- 5: constrain \(C_\mathrm{p}(T)\), \(\frac{d C_\mathrm{p}}{dT}\), \(\frac{d^2 C_\mathrm{p}}{dT^2}\), \(\frac{d^3 C_\mathrm{p}}{dT^3}\), and \(\frac{d^4 C_\mathrm{p}}{dT^4}\) to be continuous at Tint
Note that values of continuity of 5 or higher effectively constrain all the coefficients to be equal and should be equivalent to fitting only one polynomial (rather than two).
Returns the fitted NASA
object containing the two fitted
NASAPolynomial
objects.
toWilhoit
(self, B=None) → Wilhoit¶Convert the Benson model to a Wilhoit model. For the conversion to succeed, you must have set the Cp0 and CpInf attributes of the Benson model.
B: the characteristic temperature in Kelvin.