iFunc_Sqw4D/thermochemistry: compute thermodynamic quantities for 4D S(q,w) models.
compute thermodynamics quantities for a 4D S(q,w) Model.
When missing, the phonon (vibrational) density of states (vDOS) is estimated
from e.g. the evaluation of the 4D sqw phonons object.
The input 4D model should be e.g. a 4D phonon one, with axes qh,qk,ql,energy
in [rlu^3,meV]. The evaluation of the model should provide the density of states
in model.UserData.DOS as an iData object.
the function returns an array of iData objects:
DOS [modes/energy unit/unit cell]
DOS_partials DOS partials (one per mode)
entropy S [eV/K/cell]
internal_energy U [eV/cell]
helmholtz_energy F [eV/cell]
heat_capacity at constant volume Cv [eV/K/cell]
input:
s: a 4D sqw phonons model [K,H,L,Energy] (iFunc)
T: temperature range. When not given, T=1:500 [K]
options: can be 'plot' to display the results.
The 'newplot' option does the same but opens a new figure instead of
re-using an existing one.
output:
t: structure with [DOS, DOS_partials, S U F Cv ]
fig: figure handle
Reference: https://wiki.fysik.dtu.dk/ase/ase/thermochemistry/thermochemistry.html#background
D.A. McQuarrie. Statistical Mechanics. University Science Books, 2000.