Desorption of excited H* atoms from free clusters Ar/CH4 and solid Ar doped with CH4

Abstract

Desorption of excited hydrogen atoms was detected from both solid Ar doped with CH4 and free nanoclusters Ar/CH4 at irradiation with an electron beam. It was monitored by an emission of the Lyman-a line. Measurements of cathodoluminescence (CL) spectra in the VUV range were performed within the CH4 concentration limits 0.1–10% in the solid matrix. The CL of free clusters with an average size of 1200 atoms per cluster was detected from pure Ar cluster jet and from Ar clusters doped with 0.1% CH4. The mechanisms of desorption of electronically excited H* atoms from solids and clusters are proposed on the basis of an analysis of energy transfer pathways with the final stage of relaxation — population of the n = 3 state of hydrogen atoms.