Analyzing the Photodetachment Cross Section of H^(-) in Parallel Electric and Magnetic Fields

We studied the photodetachment of H^(-) in the presence of parallel electric and magnetic fields.This system is an important model that demonstrates the effects of closed-orbits and their bifurcations on the quantum spectra.Using Poisson's summation formula,we have obtained a reduction formula that represents the cross section a sum of oscillations.The reduction formula is valid uniformly.We compare it with the predication from the closed-orbit theory.