Defect-related relaxation processes in irradiated rare gas solids

Electronic and atomic relaxation processes in preirradiated solid Ar doped with N 2 were studied with a focus on the role of radiative electronic transitions in relaxation cascades. Combining methods of activation spectroscopy - thermally stimulated and photon-stimulated exoelectron emission, a new channel of relaxation induced by photon emission from metastable N atoms was detected. It was shown that in insulating materials with a wide conduction band photons of visible range can release electrons from both kinds of traps - shallow (lattice defects) and deep thermally disconnected ones. Correlation in the charge recombination reaction yield and the yield of low temperature desorption - important relaxation channel in a preirradiated solid - clearly demonstrates interconnection between atomic and electronic processes of relaxation.     

About non-linear realization of quantumSL q(2, R) group

Published in Teoreticheskaya i Matematicheskaya Fizika, Vol. 95, No. 2, pp. 183–186, May, 1993.     

Exoelectron emission from solid nitrogen

Solid nitrogen was investigated by activation spectroscopy methods – thermally stimulated luminescence and thermally stimulated exoelectron emission (TSL and TSEE) in combination with luminescence analysis. TSEE from solid nitrogen pre-irradiated by an electron beam was measured and investigated for the first time. A set of peaks both in TSL and TSEE were observed. It was found that one of the peaks in the TSEE curve is caused by release of electrons in the course of the α-β phase transition of solid nitrogen. The corresponding activation energy was estimated.     

Thermally stimulated exoelectron emission from solid neon

In spite of the negative electron affinity of Ne atoms, appreciable concentrations of electrons can be trapped in solid neon layers formed by depositing the gas on a cold substrate with concurrent electron irradiation. These are trapped at defect sites, and can be promoted into the conduction band in an annealing experiment. They can then recombine with positive charges producing vacuum ultraviolet "thermoluminescence," but can also be extracted from the solid, and detected as an "exoelectron" current. The thermally stimulated exoelectron emission profiles of the electron current versus temperature reveal two broad features near 7.5 and 10 K. These are shown to correspond to two distributions of electron trapping sites with slightly differing activation energies. For the narrower, higher temperature maximum, an average activation energy of about 23 meV is deduced, in good agreement with predictions based on the theory of electronic defect formation.     

Radiation effects, energy storage and its release in solid rare gases

An irradiation of solid argon sample by electrons ionizes the Ar atoms, and part of the beam energy is stored in the solid mainly in the form of self-trapped Ar(2)(+) holes. The pre-irradiated samples are investigated by methods of the so called "activation spectroscopy". During their controlled warm-up three thermally stimulated effects are observed and, in our experiments, simultaneously monitored: a VUV emission resulting from neutralization of the Ar(2)(+) holes by electrons, an anomalous desorption of surface atoms, and an exoelectron emission. A comparison of experiments with linear and step-wise sample heating shows clearly that all three processes are intimately connected. The heating detraps electrons, which neutralize the Ar(2)(+) holes resulting in a bound-free emission of argon dimers, centered around 9.7 eV. The excess energy set free during this process may dislodge surface atoms leading to an anomalous, low temperature, pressure rise. Some of the electrons can also be directly extracted from the sample and detected as an exoelectron current. The experiments provide information about the depth of electron traps, and indicate that there is a nearly continuous distribution of trapping energies.     

On sums of narrow and compact operators

We prove, in particular, that if E is a Dedekind complete atomless Riesz space and X is a Banach space then the sum of a narrow and a C-compact laterally continuous orthogonally additive operators from E to X is narrow. This generalizes in several directions known results on narrowness of the sum of a narrow and a compact operators for the settings of linear and orthogonally additive operators defined on Köthe function spaces and Riesz spaces.

     

A study of regimes for convective heating of deformable bodies with heat sources

We discuss a numerical/analytic method of solving the problem of determining regimes for heating electrically conducting elastic bodies using convection and electromagnetic radiation so as to optimize energy consumption. We give the results of studies of the temperature fields and stresses, and also the optimal heating regimes for a hollow glass ball.Translated fromMatematichni Metodi ta Fiziko-Mekhanichni Polya, Vol. 40, No. 3, 1997, pp. 160–165.     

Charging effects in an electron bombarded Ar matrix and the role of chemiluminescence-driven relaxation

The relaxation processes in pure and doped Ar films preirradiated by an electron beam are studied with the focus on charging effects. Correlated real time measurements have been performed applying current and optical activation spectroscopy methods. Thermally stimulated exoelectron emission and thermally stimulated luminescence are detected in the vacuum ultraviolet and visible range. An appreciable accumulation of electrons in the matrix is found, and prerequisites for negative space charge formation are ascertained. The part played by pre-existing and radiation-induced defects as well as dopants is considered and the temperature range of the electron trap stability is elucidated. It is shown that laser-induced electron detachment from O(-) centers results in an enhancement of electron detrapping via the chemiluminescence mechanism, viz. neutralized and thermally mobilized O atoms recombine. Formation of O(2)* results in the emission of visible photons. These photons act as a stimulating factor for electron release and transport, terminating in exoelectron emission and charge recombination. Chemiluminescence therefore plays an important role in the decay of charged centers.