http://dspace.nbuv.gov.ua:80/handle/123456789/128388 2026-04-13T14:12:11Z http://dspace.nbuv.gov.ua:80/handle/123456789/129227 Deposition of mass-selected ions in neon matrices: CS₂⁺ and C₆F₆⁺ Lorenz, Martin; Bondybey, Vladimir E. Infrared and visible absorption spectra and laser-induced fluorescence (LIF) and excitation spectra are obtained for several simple cations deposited from a mass-selected ion beam. In the present preliminary study we demonstrate successful and clean mass selection by presenting spectra of samples obtained by depositing the isotopic ³⁴S¹²C³²S⁺ ion in natural isotopic abundance, and analyzing its spectrum. Spectra of C₆F₆⁺ deposited from a 20 eV ion beam exhibit quite different inhomogeneous line profiles, suggesting that even the relatively low kinetic energy results in considerable damage to the solid. Analysis of the spectra indicates that the Jahn–Teller-distorted vibrational structure in the doubly degenerate ground state of C₆F₆⁺ is strongly perturbed in the newly formed sites, which are presumably of lower symmetry. A 33–46 cm−1 splitting of the origin and other totally symmetric bands in emission is tentatively attributed to the spin–orbit splitting in the ²E₁g ground state. 2000-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/129226 Low-temperature anomalies in the magnetic and thermal properties of molecular cryocrystals doped with oxygen impurity Freiman, Yu.A.; Tretyak, S.M.; Jeżowski, A. The magnetic properties of oxygen pair clusters are investigated theoretically for different cluster geometries which can be realized by doping molecular cryomatrices with oxygen. Anomalous temperature and pressure behavior of the magnetic susceptibility, heat capacity, and entropy is predicted. It is proposed to use these anomalies for studying the parameters characterizing the oxygen clusters and the parameters of the host matrix: the effective spin-figure interaction constant D for the molecule in the matrix, the exchange parameter J, and the number of pair clusters Np, which can deviate markedly from the purely random value Np=6Nc² (N is Avogadro’s number, and c is the molar concentration of the impurity). The data on the magnetic susceptibility may be used to analyze the character of the positional and orientational short-range order in the solid solution. The value of D contains information about the orientational order parameter; the distance and angular dependence of the exchange interaction parameter are still subject to discussion in the literature. The temperature dependence of Np contains information about diffusion and clusterization processes in the system. 2000-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/129225 Thermal conductivity of solid krypton with methane admixture Dudkin, V.V.; Gorodilov, B.Ya.; Krivchikov, A.I.; Manzhelii, V.G. The thermal conductivity of CH₄–Kr solid solutions is investigated at CH₄ concentrations 0.2–5.0% in the temperature range 1.8–40 K. It is found that the temperature dependence of the thermal conductivity has features typical of resonance phonon scattering. The analysis of the experimental results shows that the main contribution to the impurity-caused scattering of phonons is made by the scattering on rotational excitations of the nuclear spin T-species of CH₄ molecules. The phonon–rotation interaction parameter is estimated. 2000-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/129224 A synchrotron radiation study of high-lying excited states of matrix-isolated atomic magnesium Kerins, Paul; Healy, Brendan; McCaffrey, John G. Previous steady-state and time-resolved luminescence spectroscopy of 3p ¹P₁ atomic magnesium, isolated in thin film samples of the solid rare gases, has been extended to include the higher energy 4p ¹P₁ excitation. Well resolved site splittings have been recorded in Mg/Ar samples for excitation to the 4p ¹P₁ level. A small red shift in the absorption energy to the 4p ¹P₁ level for Mg/Ar contrasts with a small blue shift on absorption to the 3p ¹P1 level. Direct emission from the 4p ¹P1 level is not observed in any of the rare gas matrices, instead intense emission from the low energy 3p ¹P1 level is. Measurements of the emission decay curves in Mg/Ar have revealed slow rates in the steps feeding the 3p ¹P₁ level following 4p ¹P₁ excitation. The reason for the differential shifting of the 4 p ¹P₁ and 3p ¹P₁ levels as well as the lack of direct 4p ¹P₁ emission is thought to be related to the strong binding interaction between Mg in the 4p ¹P₁ state and the rare gases. 2000-01-01T00:00:00Z