| Popis: |
Many scientific and technological problems for which solution the examination of the isotope composition or its modification as a result of certain processes are required. So, for example, in geology it is the problems related to geochronology, isotope geochemistry (including shaping of the earth crust, examination of a glaciers etc.). In the space researches: a problems of the isotope space geochemistry, the space chemistry and the space geochronology (processes of shaping of a planets, comets, asteroids; the history of shaping of a chemical elements in the Universe) (Shukolyukov Yu.A., 1996). In the nuclear power: the fuel and other functional materials of the nuclear and thermonuclear reactors. And many other things. Now are known many processes in which a diversions from the natural abundances of isotopes are observed. In the physics and chemistry the following processes are most known: a. The kinetics processes; b. The reactions of the isotopic interchanging; These processes are responsible for a isotope modifications in the following physical and chemical phenomena: evaporation, condensation, melting, crystallization, diffusion and dissociation. Thus it is known, that chemical bonds with a heavy isotopes more strongly than the same bonds with a light isotopes. In general terms, all isotopic effects can be parted on two types: 1. Kinetic based on different velocities of processes and caused by the fact that in the aggregate of interacting molecules the particles with smaller mass possess greater velocity; 2. Thermodynamic which are reflection of a different energy states of the system. A composition with heavy isotopes possesses a smaller reserve of a free energy, than the same compositions with a light isotope (Galimov E.M., 1981). It is now know also that deriving of the large isotopic effect in certain process are necessary: a high relative odds of masses, a high degree of chemical bond covalence, modifications of a oxides states, a modification of a phase or modular state. Last researches of isotopic effects in the chemistry have led to discovery of one more view of the isotopic effect fractionation of nuclear-isotopes on a nuclear magnetic moment (Buhanchenko A.L., 2007). The possibility of detection of nuclear polarization is a new |
