darkhistory.physics.photo_ion_xsec

darkhistory.physics.photo_ion_xsec(eng, species)

Photoionization cross section in cm².

Cross sections for hydrogen, neutral helium and singly-ionized helium are available.

Parameters:

engndarray

Energy to evaluate the cross section at.

species{‘HI’, ‘HeI’, ‘HeII’}

Species of interest.

Returns:

xsecndarray

Photoionization cross section.