ANGULAR DISTRIBUTION OF DESORBED MOLECULES

X.W. LI; B.Z. GUO; S.H. LIN; H. MA

doi:doi:10.1051/jp4:1991203

Proceedings of the Eighth European Conference on Chemical Vapour Deposition / Actes de la 8ème Confèrence Européenne sur les Dépôts Chimiques en Phase Gazeuse

J. Phys. IV France 02 (1991) C2-33-C2-38
DOI: 10.1051/jp4:1991203

ANGULAR DISTRIBUTION OF DESORBED MOLECULES

X.W. LI¹, B.Z. GUO¹, S.H. LIN² and H. MA²

¹ Department of Electronics, Hebei University, Baoding 071002, P.R. China
² Department of Chemistry, Arizona State University, Tempe, AZ 85287-1604, U.S.A.

Abstract
A macroscopic theory for treating the angular distribution of desorptive products due to thermal or photo-assisted desorption is reported. The angular distribution has been attributed to either the rotational relaxation of adsorbed molecules or the angular dependence of the rate constant or both. By using the theory of angular momentum, explicit expressions of the desorption yields for the cases of constant temperature or heating with a constant rate were obtained. Based on the theory, some experimental results such as the desorption of CO₂ from Pt (111) surface have been explained and the effect of crystal orientation of the substrates was discussed as well.