darkhistory.physics.coll_exc_xsec

darkhistory.physics.coll_exc_xsec(eng, species=None, method='old', state=None)

e-e collisional excitation cross section in cm².

see under method for references

Parameters:

eng : float or ndarray

Abscissa of kinetic energies.

species : {‘HI’, ‘HeI’, ‘HeII’}

Species of interest.

method : {‘old’, ‘MEDEA’, ‘new’}

if method == ‘old’, see 0906.1197; if method == ‘MEDEA’, see Mon. Not. R. Astron. Soc. 422, 420–433 (2012); if method == ‘new’, nothing yet

Returns:

float or ndarray

e-e collisional excitation cross section.