Raman spectroscopy of KAl(MoO4)(2) and NaAl(MoO4)(2) single crystals

Polarized Raman spectra were obtained for KAl(MoO4)(2) and NaAl(MoO4)(2) cr ystals at ambient temperature, Raman studies of NaAl(MoO4)(2) were also per formed over a wide temperature range, 100-930 K. The assignment of the obse rved bands to the respective stretching, bending and lattice modes was prop osed. The temperature dependence of the Raman spectra showed that NaAl(MoO4 )(2) remains in the monoclinic structure up to the melting temperature. How ever, the monoclinic distortion from the trigonal D-3d(3) structure is rela tively small at high temperatures and increases continuously with decreasin g temperature. Copyright (C) 1999 John Wiley & Sons, Ltd.