Raman spectra of molecular crystals at high pressures. Part VI - bromine cyanide

Raman spectra of solid bromine cyanide, BrCN, at ambient temperature and at pressures up to 12 GPa are reported. The spectra evolve smoothly and there is no evidence of any structural phase transitions or of any major molecul ar distortions in this pressure range. The four main peaks (librational, be nding and two stretching modes) all show increases in wavenumber with press ure, with that for the libration being most pronounced, as a result of a th reefold strengthening of intermolecular bonding. At high pressures, prolong ed exposure to large visible photon fluxes causes the onset of irreversible colour changes attributed to molecular dissociation and the release of bro mine, Copyright (C) 2000 John Wiley & Sons, Ltd.