Effective He * deexcitation energies in penning ionization spectroscopy of co adsorbed on Ni

Abstract

In Penning ionization spectroscopy of adsorbates the effective excitation energy stored in the metastable noble gas beam atoms depends on their interaction with the target. In the present contribution we discuss and calculate the dependence of the effective He * deexcitation energy in collisions with CO adsorbed on Ni and Pd which have been studied recently. The calculations demonstrate that both short and long range components of the interaction between He * (He) and the CO adsorption complex are needed to establish the relevant magnitude of the change of the effective deexcitation energy observed experimentally.