Nonthermal energy level populations in excited oh electronically desorbed from alkali halide surfaces

Abstract

Analysis of the A 2 Σ + → X 2 Π emission from excited OH radicals desorbed from alkali halide surfaces by low energy electron bombardment indicates strongly nonthermal energy partitioning among the rotational levels of the excited state. In particular, a difference in the population of the F 1 and F 2 states is observed. This alternation becomes stronger as the sample temperature is lowered below room temperature, indicating that the broken symmetry between the F 1 and F 2 states is sufficiently weak that thermal effects can partly mask it near room temperature.