Velocity-Dependent Internal Energy Distributions of SiCl Molecules, Laser Sputtered from Silicon in a Chlorine Atmosphere

Abstract

A silicon (111) surface is exposed to chlorine gas and irradiated by 248 nm photons. The vibrational and rotational energy distributions of ground-state SiCl molecules ejected from the surface are determined using laser-induced fluorescence. The results show a strong non-Boltzmann nature and a rotational population dependent on the vibrational quantum number. Besides this, the first observation of internal energy as a function of kinetic energy is made for sputtered molecules leaving a surface. The internal excitation increases with velocity.