Vibrational interaction in rare earth perrhenates

Investigation of Raman spectra of light in rare earth perrhenate monocrystals at low temperatures (up to 5 K) has been carried out. Splitting of A1-band, corresponding to vibrations of a completely symmetric type of (ReO4)- complexes, specified by degeneration removal according to the position parity in the unit cell is detected. The experimental data are processed by the LSM. It has been found that the magnitude of splitting due to a vibrational interaction increases with the decrease in splitting of frequencies corresponding to vibrations of crystallographically nonequivalent complexes. Great difference in the magnitudes of splitting for Nd and Dy perrhenates (approximately 1.5 times) is explained on a supposition that the efficiency of vibrational interaction of crystallographically nonequivalent complexes exceeds considerably the corresponding quantity for crystallographically equivalent complexes