RAMAN-SCATTERING IN A [(CH3)(2)NH2](5)CD3CL11 CRYSTAL

Raman spectra of [(CH3)(2)NH2](5)Cd3Cl11 (DMAPCC) single crystals were studied over the range 10-3200 cm(-1) between 100 and 360 K. The chan ges in the external and internal mode region were observed and charact erized. In particular, the symmetric stretching vibration of the dimet hylammonium (DMA) group at 890 cm(-1) splits continuously over the tem perature range 360-110 K. The analysis of the DMA stretching mode base d on an order-disorder model showed the presence of competition betwee n long-range interactions in the disordered DMA(3) subsystem and short -range interactions between anions and cations, The change in the wave number behaviour of the 893 cm(-1) mode corroborated the presence of a phase transition at 170 K. (C) 1998 John Wiley & Sons, Ltd.