PHONON RELAXATION PROCESSES IN MOLECULAR-CRYSTALS (CS2) AT HIGH-PRESSURE AND LOW-TEMPERATURE

Solid CS2 is investigated in a diamond anvil cell in the pressure range of 0.4-2.4 GPa at 20 K by means of high resolution Raman spectroscopy. The pressure dependent linewidths of several selected modes are determined and discussed in the framework of anharmonic lattice dynamics considering depopulation and dephasing processes which are influenced by anharmonic terms in the crystal potential and multiphonon density of states. The relaxation of OMEGA-at high pressure is mainly governed by a four phonon down process via nu2 and two lattice phonons, whereas OMEGA+ decays in a state of the two phonon band directly.