Rotationally excited NO molecules incident on a graphite surface: molecular rotation and translation after scattering
Abstract
The redistributions of rotational and kinetic energies of NO molecules scattered from an atomically flat graphite surface have been investigated. With the use of a heatable nozzle the rotational temperature of the incident molecules could be varied between 20 K and 650 K, the average incident kinetic energy remained constant at about 1000 cm -1. Usually the in-plane angular distributions consist of a broad lobe of specularly scattered molecules together with a diffuse background. The diffuse component exhibits rotational accommodation to the surface temperature irrespective of the rotational energy of the incident molecules. The rotational temperature of the specular component is linearly proportional to the incident rotational temperature of NO. Saturation behavior is found when the surface temperature is increased up to 700 K. Additional molecular rotational energy in the incident channel is partially converted into kinetic energy of the scattered molecules. The relation between translational and rotational degrees of freedom is discussed on the basis of our observations.
- Publication:
-
Surface Science
- Pub Date:
- March 1997
- DOI:
- 10.1016/S0039-6028(96)01212-5
- Bibcode:
- 1997SurSc.374..181H