Optically-stimulated desorption of 'hot' excimers from pre-irradiated Ar solids

Electronically-induced desorption from solid Ar pre-irradiated by a low-energy electron beam was investigated by activation spectroscopy methods - photon-stimulated exoelectron emission and photon-stimulated luminescence in combination with spectrally-resolved measurements in the VUV range of the spectrum. Desorption of vibrationally excited argon molecules Ar2^*(v) from the surface of pre-irradiated solid Ar was observed for the first time. It was shown that desorption of 'hot' Ar2^*(v) molecules is caused by recombination of self-trapped holes with electrons released from traps by visible range photons. The possibility of optical stimulation of the phenomenon is evidenced.Comment: The complete version of the paper will be published in Fiz. Nizk. Temp. (Low Temp. Phys.

Evidence for the classical integrability of the complete AdS(4) x CP(3) superstring

We construct a zero-curvature Lax connection in a sub-sector of the superstring theory on AdS(4) x CP(3) which is not described by the OSp(6|4)/U(3) x SO(1,3) supercoset sigma-model. In this sub-sector worldsheet fermions associated to eight broken supersymmetries of the type IIA background are physical fields. As such, the prescription for the construction of the Lax connection based on the Z_4-automorphism of the isometry superalgebra OSp(6|4) does not do the job. So, to construct the Lax connection we have used an alternative method which nevertheless relies on the isometry of the target superspace and kappa-symmetry of the Green-Schwarz superstring.Comment: 1+26 pages; v2: minor typos corrected, acknowledgements adde

Oxygen-driven relaxation processes in pre-irradiated Ar cryocrystals

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

Laser light-stimulated exoelectron emission from solid Ar pre-irradiated by an electron beam

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

Oxygen-driven relaxation processes in pre-irradiated Ar cryocrystals

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

Thermoactivation spectroscopy of solid Ar doped with N₂

A new modification of low-temperature activation spectroscopy technique for real-time correlated study of relaxation processes in cryogenic solids was developed. This enabled us to measure simultaneously 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 N₂ exposed to irradiation by low-energy electron beam (500 eV) during deposition. The TSEE and TSL yields were measured at the heating rate of 3.2 K/min. The emissions of molecular (A³Σu⁺ → X¹Σg⁺ transition) and atomic (²D → ⁴S transition) nitrogen in the TSL spectra and their temperature behavior were studied. Drastic changes in the intensity distribution of the molecular progression were observed with temperature rise. In low-temperature range «hot» vibrationally unrelaxed transitions were detected in contrast to «cold» vibrationally relaxed transitions observed in «high» temperature TSL. The mechanisms of the processes resulting in TSL in whole temperature range of Ar solid occurrence are suggested

Oxygen-driven relaxation processes in pre-irradiated Ar cryocrystals

Relaxation processes in oxygen-containing Ar cryocrystals pre-irradiated by low-energy electrons are studied with the focus on the role of diffusion controlled atom-atom recombination reaction of oxygen in the relaxation cascades. The results of correlated in real time 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 of the radiative mechanism of electron detrapping triggering the relaxation cascades is obtained