FAR-INFRARED STUDY OF CARBON-DISULFIDE AT HIGH-PRESSURES

Far-infrared spectra of carbon disulfide in diamond anvil cells at amb ient temperature and at pressures up to 8 GPa are reported. The freezi ng pressure is confirmed to be 1.3 GPa, and no solid state phase trans itions are observed. Above 8 GPa irreversible darkening of the sample occurs, the result of partial decomposition. Three components of the b ending mode are detected, and their peak wavenumbers all decrease slig htly with pressure, indicative of a weakening of intramolecular bondin g. The wavenumber of the single translational peak shows a substantial increase over the pressure range investigated, corresponding to a str engthening of intermolecular bonding by a factor of about 2.5.