Collision spectroscopy of the He0 + D2 system in the 1 to 2 keV energy range

Direct scattering of He0 on D2 is studied, both theoretically and experimentally, with particular emphasis on quasi-elastic scattering. Sigmund scaling is demonstrated, despite the presence of inelastic channels. This is significant, because one of the requirements in Sigmund's derivation is that no inelastic channels be open. In addition, cross sections for the quasi-elastic processes as well as the one and two electron excitation processes are studied. Some of the lowest lying excited state surfaces of the HeH2 system are calculated, as well as the portion of the ground state surface in which the He projectile is in close proximity to the H2 target. Agreement between theory and experiment for the scaling and for the cross sections indicate that some understanding of the ground state energy surface was attained. In addition, classical scattering calculations were carried out to better understand this surface and to understand the breakdown of the scaling due to velocity effects