Vibrational spectra in camoO₄ crystals with nddoption

Raman spectra were obtained in molybdates with the structural type of pure shellite -calcium molybdenum and with an impurity of neodymium: 1.1 at %, at room temperature. Based on the data obtained, a correlation diagram of group frequencies for CaMoO₄ and CaMO₄: Nd crystals was compiled. In the frequency range 843-884 cm⁻¹, full-symmetric stretching vibrations ν B-O appear, bending vibrations β O-B-O corresponds to the region 319-793 cm⁻¹, in the region 793-827 cm⁻¹, mixed bending and stretching vibrations appear. In the CaMoO₄ crystals with Nd impurity, a significant change is observed in the low-frequency region of the spectrum; maxima appear at frequencies of 108 and 202 cm⁻¹, apparently, these modes cause a displacement of the molybdenum atom. Second, in the frequency range 330 to 800 cm⁻¹, the combination lines disappear in the impurity crystal, which is observed in a pure crystal of calcium molybdenum.