Periodic trends in the reactions of atomic ions with molecular hydrogen

Abstract

One of the simplest possible reactions imaginable, that of an atomic ion with molecular hydrogen, shows a remarkable diversity in behaviour as the atomic ion is varied throughout the periodic table. Studies of these reactions reveal the fundamental changes that occur in the chemistry as the number of electrons is systematically varied. Here, we review our work on the kinetic energy dependence of these reactions as studied by using guided ion beam mass spectrometry. Substantial progress has been made in this area and now includes studies of 44 elements. This experimental technique is shown to provide unprecedented detail in reaction excitation functions over an extremely wide kinetic energy range. These studies allow an understanding of such effects as the reaction thermochemistry, electronic degeneracy, adiabatic versus diabatic potential energy surfaces and spin-orbit coupling.