RAMAN-SPECTROSCOPIC STUDY OF LIVO3 AND LIVO3-CENTER-DOT-2H(2)O

The Raman spectra of lithium metavanadate, LiVO3, have been recorded i n the temperature range 300-10 K. A phase transition was observed at a bout 70 K. A soft mode was found for the room temperature phase at 55 cm(-1), while at least two soft modes were observed for the low temper ature phase at 213 and 289 cm(-1) respectively. The hydrated samples L iVO3 . 2H(2)O were also studied. It was found that the samples grown f rom supersaturated aqueous solutions contained only water molecules ad sorbed on the crystal surface and these can be eliminated by heating t o 70 degrees C, while the samples grown from unsaturated solution have water molecules inside the sample as well as on the surface, and a hi gher temperature of 130 degrees C is needed to release the internal wa ter. The hydrated samples may transform to LiVO3 through an intermedia te phase.