Note

You can download below the full example code and run it with 🔬 Radis-Lab,

Partition Functions from spectroscopic constants

RADIS can calculate equilibrium and non-LTE Partition Functions from a given set of spectroscopic constants using a Dunham expansion.

Calculations use the PartFunc_Dunham class

Default spectroscopic constants and spectroscopic models used are given in default spectroscopic constants. You can also use your own set of spectroscopic constants.

See Also

PartFuncHAPI

from radis.db.molecules import Molecules
from radis.levels.partfunc import PartFunc_Dunham

isotope = 1
electronic_state = "X"
S = Molecules["CO"][isotope][electronic_state]

# Equilibrium partition functions :
Qf = PartFunc_Dunham(S)
print(Qf.at(T=3000))  # K

# Nonequilibrium partition functions :
print(Qf.at_noneq(Tvib=2000, Trot=1000))  # K