Velocity and angular distributions of H2 (v=1 J=1) scattered from Cu (110) and Cu (111)

摘要

Abstract: The scattering of vibrationally and rotationally state-selected H$-2$/ from Cu(110) and Cu(111) surfaces has been studied. Stimulated Raman scattering is used to pump a fraction of the incident flux in a supersonic beam of H$-2$/ into the J equals 1 rotational state of the first excited vibrational state. Resonance-enhanced multiphoton ionization (REMPI) is used to detect incident and scattered H$-2$/ in this state. Time-of-flight spectra are recorded as a function of the distance from the REMPI probe to the surface and scattering angle. These data are fit to a model whose parameters describe the velocity and angular distribution of the scattered molecules. The model permits a determination of flux from the density-sensitive measurements. Its use to derive a quantitative estimate of the absolute survival probability for the pumped state is discussed. !12