ORTHO-PARA HYDROGEN CONVERSION ON METAL SURFACES

Abstract

EELS experiments of H 2 absorbed at low temperature on Noble Metals have indicated that the o-p H 2 conversion can be very fast on metals, even in absence of chemisorption, in contradiction with the usual belief that the catalyst must be magnetic to be efficient. We examine a large family of processes which convert the hydrogen molecules on the basis of the emission of metal electron-hole pairs. The most efficient mechanism found is the Coulomb-Contact one based on a virtual charge transfer, back and forth, from the metal to the molecule, having a rate in agreement with experiment.