Spatially separated stable charge centers, self-trapped holes and trapped electrons, were generated in Ar cryocrystals by a low-energy electron beam. A combination of the cathodoluminescence (CL) and photon-stimulated exoelectron emission (PSEE) methods was used to monitor center formation and a selected relaxation channel-exoelectron emission. It was found that photon-promoted electron current decreased exponentially under irradiation with the laser operating in the visible range. The influence of the laser parameters (power and wavelength) on the characteristic lifetime of exoelectron emission is discussed. Effective bleaching of the low-temperature peaks of thermally stimulated exoelectron emission by the laser light in a visible range is observed. (c) 2007 American Institute of Physics.

Relaxation processes in oxygen-containing Ar cryocrystals pre-irradiated by low-energy electrons are studied with the focus on the role of the diffusion-controlled atom-atom recombination reaction of oxygen in the relaxation cascades. The results of real-time-correlated measurements of thermally stimulated phenomena are presented. The experiments have been performed using activation spectroscopy methods-thermally stimulated exoelectron emission and spectrally resolved thermally stimulated luminescence. Solid evidence for the radiative mechanism of electron detrapping triggering the relaxation cascades is obtained. (c) 2006 American Institute of Physics.

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 1100 nm. This paper presents the results on TSL and TSEE from solid Ar doped with N-2 exposed to irradiation by a low-energy electron beam (500 eV) during deposition. The TSEE and TSL yields were measured at a heating rate of 3.2 K/min. The emissions of molecular (A(3)Sigma(+)(u)-> X-1 Sigma(+)(g) transition) and atomic (D-2 -> S-4 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. (c) 2007 American Institute of Physics.