Eur. Phys. J. D 4, 309-319 (1998)
https://doi.org/10.1007/s100530050214

Dissociative excitation of the fluoromethanes by electron impact

Fachbereich Experimentalphysik, Universität des Saarlandes, 66041 Saarbrücken, Germany

Corresponding author: ^a okeller@rz.uni-sb.de

Received: 25 February 1998
Revised: 29 May 1998
Accepted: 23 June 1998
Published online: 15 December 1998

Abstract

Emission spectra following electron impact on molecules of the homologous series of fluoromethanes CH_xF with have been investigated from the near infrared at 700 nm to the ultraviolet VUV-spectral region at 100 nm. Earlier experimental data for the visible and ultraviolet spectral region were revised and evaluated again on the basis of reliable new data for the dynamic viscosity of the molecules. The measurement of absolute and relative cross-sections were systematically extended into the VUV region from 100 nm to 200 nm. The examination of atomic lines as well as molecular band systems in the VUV gives further insight into the dissociation mechanism and shows that many excited levels even of atomic and molecular species cannot be populated directly, but only by transitions from higher-lying energy levels. Simple steric effects can be distinguished from more complex transition phenomena.