Calculated inverse photoemission cross sections from adsorbed molecules

Abstract

A quantum-theoretical treatment is applied to calculate the cross section for emission of photons produced in inverse photoemission from an adsorbed molecule. Careful consideration of the type of potential that may be used in such calculations shows that photoemission and inverse photoemission from localized levels may be treated as time-reversed processes only above some minimum energy, approximately four times the threshold energy. In situations where time reversal may be used, a simple formula is derived relating the cross sections for photoemission and inverse photoemission. Examination of cross sections shows that the shape resonance frequently observed in photoemission as a final-state effect may manifest itself in inverse photoemission as an initial-state effect.