[en] The effect of phase transitions on luminescence centre parameters in ammonium-halide crystals (AHC), activated by heavy metal ions, on the process of electron excitation energy transfer and on the process of formation of radiation defects under X-irradiation has been investigated. In AHC, activated by Tl⁺, Sn²⁺, In⁺, Pb²⁺ ions, a number of absorption (excitation) bands, which are compared with the ¹S₀ → ³P₁ (sup(1)Asub(1g) → sup(+)Tsub(1u)) (A-band), ¹S₀ → Pb²⁺ (sub(1)Asub(1g) → sup(3)Esub(u)+sup(3)Tsub(2u)) (B-band) and ¹S₀ → ¹P₁ (sup(1)Asub(1g) → sup(1)Tsub(1u)) (C-band) transitions in ions with the S²-electron configuration, is observed. The spectral bands are well approximated by GaUss functions. It is shown, that the phase transitions affect differently by the dynamic and static parameters of luminescence centres, electron-, hole- and exition migration; defect formation. One should take all this into account, when using some or other materials as luminophors, scintillators, dosemeters and in other devices in which the properties of various defects are employed

[en] On the base of the GEANT general program system for simulating high energy physics experiments a program package for Simulating some neutral resonance production reactions has been created. New system of subprograms provides taking into account of all basic characteristics of the ''Photon-Masser'' installation. It could serve both for calculating the efficiency of measurements already performed, and for preparing new experiments. Electron ionization losses, production of electron-positron pairs induced by gamma-quanta, multiple scattering and electron bremsstrahlung are taken into account. The program has been used for processing results of the experiment on measurement of partial width of eta → π⁰γγ decay and for determining the optimal geometry of experiment on the study of cumulative production of eta- and ω-mesons. It is shown that results of calculation by this program agree well with ex. periment

[en] Main spectral features of single valence copper ions and silver ions in ammonium halides crystal are considered. Certain parameters of electron-phonon interaction, probably nonradiative transitions and their change under phase transition are revealed. (author)

[en] The brief review of various theories of origin of the centers of crystallization and their features is given. The simple model from which the critical radius of a germ follows, that is offered practically, does not depend on a grade of atoms of a liquid phase which is exposed to crystallization. (author)

[en] The temperature dependences of photoluminescence are investigated. It is established that the strong electron-phonon coupling takes place in these crystals. The non-radiating transitions at the centers of the luminescence are thermally activated. (author)

[en] Spectral - luminescence characteristics of ammonium iodide crystals irradiated by X-ray quants are investigated. The appearance of 3.7 eV band in reflection spectrum is related to the absorption of V_k-centres. The 3.3 eV band is conditioned by the absorption of iodine aqueous solutions, as well as that of iodine adsorbed on the surface. In X-ray luminescence spectrum the band related to radiation decay of authorized excitons is observed. Thermostimulated luminescence spectra of irradiated ammonium iodide crystals are also studied

[en] The results of experimental investigation of optical spectra of two-valent ytterbium in ammonium halogen crystals are presented. Sharp changes in spectra are observed in the region of orientation phase transition, that differs considerably Yb²⁺ ions from ions with other electron configuration

[en] In the work it is shown the perspectiveness of usage of oxo-halides of bismuth and antimony in the capacity of effective scintillator and radio-phosphors

[en] Formation of radiation-induced defects in activated by two-valence tin ions ammonium chloride crystals is investigated. Sharp difference if their spectra from spectra of irradiated crystals of halogen alkali metals is observed and it relates to the influence of complex cation NH₄⁺ on the defect formation mechanism. At phase transition jump-like change in spectra of induced absorption occurs

[en] The dimensional effects appearing in magnetic, electrical, optical and other physical properties of fine particles and thin films are studied. The model describing these effects is suggested as well as the methods on its base for determination of surface tension (surface energy) of solids including nanoparticles and nanofilms. The comparison of this model with the existing models and experimental data is carried out