Study of vibrational spectra of hexaoxyrhenates, Ba2LiReO6 and Ba2NaReO6

Vibrational spectra of hexaoxyrrenates Ba26LiReO6, Ba27LiReO6 and Ba2NaReO6, crystallized in the structure of cubic perovskite are measured. On the basis of the results of theoretical- group analysis of crystal vibrations and isotopic shifts, observed in the spectra, the attribution of vibrations according to symmetry types is carried out. Certain distortion of the cubic structure, at which atoms of alkali elements hold their positions in lattice points is pointed out. The theoretical calculation of frequencies and forms of normal vibrations is made according to the method of polymer chains in the valent-force field. The force field of the crystal is evaluated. The analysis of the vibration dynamics is presented