Laser investigation of the dynamics of molecule-surface interaction
Abstract
The internal energy distribution of NO molecules scattered from different solid surfaces (Pt(111), graphite, and Pt(111) covered with adlayers) was investigated by the laser-induced fluorescence method. In the case of the NO/graphite system, moreover, the velocity distribution of the scattered molecules could be measured in a time-of-flight experiment. The rotational energy distribution, which can always be described as a Boltzmann distribution, exhibits only partial accommodation to the surface temperature for all surfaces investigated. The angle and state-resolved velocity distributions of the NO/graphite system show at low surface temperatures the coexistence of a quasi-specular and an isotropic part. The diffusively scattered NO molecules gain rotational energy, but transfer much more translational energy to the surface, so that the energy balance is considerably negative. For the specularly scattered molecules, however, energy loss and gain are balanced, but only at low surface temperatures. With increasing temperatures the scattered molecules gain translational energy, but the rotational energy stays constant, resulting in a substantial energy transfer from the surface to the scattered NO molecules. On the basis of these results a rather complete description of the behaviour of the NO molecules during the scattering process can be presented.
- Publication:
-
Nuclear Instruments and Methods in Physics Research A
- Pub Date:
- September 1985
- DOI:
- 10.1016/0168-9002(85)90018-X
- Bibcode:
- 1985NIMPA.239..425H