rmgpy.thermo.ThermoData¶
- class rmgpy.thermo.ThermoData(Tdata=None, Cpdata=None, H298=None, S298=None, Cp0=None, CpInf=None, Tmin=None, Tmax=None, E0=None, label='', 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.
- as_dict(self) dict ¶
A helper function for dumping objects as dictionaries for YAML files
- Returns:
A dictionary representation of the object
- Return type:
dict
- comment¶
unicode
- Type:
comment
- 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
- get_enthalpy(self, double T) double ¶
Return the enthalpy in J/mol at the specified temperature T in K.
- get_entropy(self, double T) double ¶
Return the entropy in J/mol*K at the specified temperature T in K.
- get_free_energy(self, double T) double ¶
Return the Gibbs free energy in J/mol at the specified temperature T in K.
- get_heat_capacity(self, double T) double ¶
Return the constant-pressure heat capacity in J/mol*K at the specified temperature T in K.
- is_all_zeros(self) bool ¶
Check whether a ThermoData object has all zero values, e.g.:
- ThermoData(
Tdata=([300, 400, 500, 600, 800, 1000, 1500], “K”), Cpdata=([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], “J/(mol*K)”), H298=(0.0, “kJ/mol”), S298=(0.0, “J/(mol*K)”),
)
- Returns:
Whether all values are zeroes or not.
- Return type:
bool
- is_identical_to(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, orFalse
otherwise.
- is_similar_to(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, orFalse
otherwise.
- is_temperature_valid(self, double T) bool ¶
Return
True
if the temperature T in K is within the valid temperature range of the thermodynamic data, orFalse
if not. If the minimum and maximum temperature are not defined,True
is returned.
- label¶
unicode
- Type:
label
- make_object(self, dict data, dict class_dict)¶
A helper function for constructing objects from a dictionary (used when loading YAML files)
- Parameters:
data (dict) – The dictionary representation of the object
class_dict (dict) – A mapping of class names to the classes themselves
- Returns:
None
- to_nasa(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, orTrue
to keep it fixedweighting -
True
to weight the fit by \(T^{-1}\) to emphasize good fit at lower temperatures, orFalse
to not use weightingcontinuity - 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 fittedNASAPolynomial
objects.