142Luminescence theories, and the crystal field and molecular orbitals theories. This affects not only the luminescence of predominantly ionic crystals, but also of typical crystallophosphors.At the same time, kinetic theories of luminescence were being developed in great detail within the framework of the energy band theory.The application of electron paramagnetic resonance to the study of photosensitive compounds helped to give concrete expression to the chemical nature of acceptor and donor levels in the band scheme of luminescence, to the part of the electron and hole trapping played in it.Investigations into the stimulated emission of quantum generators-lasers and masers-provided a host of information on the fluorescence of rare earth ions, actinides, and some transition metal ions.Extensive studies of EPR, optical spectra, and luminescence spectra of these ions in crystals yielded detailed schemes of the energy levels, and also highly circumstantial pictures presenting spectroscopic peculiarites of such model structures as CaF2, ZnS, CaW04, A120 3, and others.A factor such as an increased interest in lunar research stimulated an appearance of a number of works on proton-luminescence, which had to serve as a model for possible lunar luminescence occurring under the influence of the solar wind. In addition to photo, cathode, and proton-luminescence also luminescence occurring under the effect of ions, X-and gamma-rays was subject to investigations. Research works covered separate domains of electroluminiscence [652, 694], chemical luminescence [600], cando luminescence [821], luminescence of organic compounds (fluorescence), and bitumens (used in petroleum geology). Fluorescent analysis has developed as a special method that finds application particularly in analyzing mineral raw materials [619, 790].The construction of electron probe microanalyzers, and of a uv microscope made luminescence serves as one of the methods used conjointly with microscopy.Technical applications furthered theoretical investigations of luminescence. At its root lay, in particular, conversions: (1) of invisible light into visible in luminescent lamps (phosphates, particularly of the apatite composition, with Sb and Mn, with Pb, TI, Sn, willemite, wollastonite with Pb and Mn) and in compounds with long-term afterglow (ZnS-Cu); (2) electron excitation into visible light, in cathoderay tubes (in radiolocation and television: ZnS and CdS with Ag); (3) X-ray emission into visible light, in X-ray screens (CaW04 , BaS04 , ZnS, CdS, Ag); (4) nuclear radiation into visible light, in scintillators (alkali haloids with TI).These are joined by thermo luminescent dosimeters used in particular for registration of nuclear explosions and installed on satellites (CaS04 : Mn, LiF: Mn).All these factors have created a situation propitious for an entirely new mineralogical significance of luminescence. A primary pre-requisite for this is changing from qualitative observations to obtaining luminescence spectra. Photorecording at low temperatures makes it...
