darkhistory.physics.coll_exc_xsec

darkhistory.physics.coll_exc_xsec(eng, species=None)

e-e collisional excitation cross section in cm².

See 0906.1197.

Parameters:

engfloat or ndarray

Abscissa of kinetic energies.

species{‘HI’, ‘HeI’, ‘HeII’}

Species of interest.

Returns:

float or ndarray

e-e collisional excitation cross section.