Thermoactivation spectroscopy of solid Ar doped with N2

Abstract

A new modification of low-temperature activation spectroscopy technique for real-time correlated study of relaxation processes in cryogenic solids is developed. This enables us to measure simultaneously the thermally stimulated exoelectron emission (TSEE) and spectrally resolved thermally stimulated luminescence (TSL) in the range from 200 to 1100nm. This paper presents the results on TSL and TSEE from solid Ar doped with N2 exposed to irradiation by a low-energy electron beam (500eV) during deposition. The TSEE and TSL yields were measured at a heating rate of 3.2K∕min. The emissions of molecular (A3Σu+→X1Σg+ transition) and atomic (D2→S4 transition) nitrogen in the TSL spectra and their temperature behavior were studied. Drastic changes in the intensity distribution of the molecular progression are observed with temperature rise. In the low-temperature range, “hot” vibrationally unrelaxed transitions are detected, in contrast to “cold” vibrationally relaxed transitions observed in “high”-temperature TSL. The mechanisms of the processes resulting in TSL in the whole temperature range of solid Ar existence are suggested.