Molecule excitation in sputtering, scattering and electron or photon induced desorption

Abstract

Simple theoretical considerations are shown to predict significant rotational and vibrational excitation of sputtered, scattered, and energetic desorbed molecules, alignment of the rotation axis, and orientation effects in dissociative and non-dissociative charge exchange cross-sections. Where available, experimental data verifying these predictions is presented. A theory of molecule-surface electronic interactions is outlined, and used to derive, from experimental data, the dependence on ionisation energy of the probability of occupation of a molecular state ( H 2 b 3 Σ u +) following scattering from a metal surface (Ni(111)). It is shown that vibrational excitation may occur as a consequence of non-dissociative charge capture. The possible role of substrate excitation (in the form of electron-hole pair creation) in vibrational quenching of ejected and scattered molecules is suggested.