Raman and infrared spectra were recorded for crystalline deoxycytidine samples at 300, 200, 100 and 10 K. Data were taken over the spectral range 20-4000 cm −1 . The wavenumbers of most vibrational modes were found to increase as the temperature was lowered. A number of peaks split into multiplets at low temperature. A new mode, observed at 375 cm −1 , is a marker band for 2 -deoxyribose in cytosinecontaining nucleic acids. Evidence is presented supporting the assignment of marker bands associated with the C3 -endo and C2 -endo puckers of deoxyribose. No clear indication was found of any structural phase transitions in this temperature range. Several hydrogen-stretching modes were found to involve hydrogen bonding. Plausible assignments of all the main features observed are suggested.

Raman spectra of solid boron triiodide, BI 3 , at ambient temperature and at pressures up to 5 GPa are reported. Because of drastic but reversible colour changes to the samples and subsequent absorption, measurements at higher pressures were not possible. Four fundamental peaks, assigned as translational, librational, bending and stretching modes, were tracked as a function of pressure. The spectra evolve smoothly and there is no evidence of any structural phase transitions or major molecular distortions in this pressure range. All modes show increases in wavenumber with pressure, with that for the two lattice modes being most pronounced. The initially 'soft' crystal at ambient pressure stiffens appreciably, with an approximately fourfold increase in intermolecular bonding at 5 GPa.

Raman and infrared spectra from 20 to 4000 cm −1 were recorded for crystalline deoxyadenosine samples at 300, 200, 100 and 10 K. The wavenumbers of most vibrational modes were found to increase as the temperature was lowered. No clear indication was found of any structural phase transitions in this temperature range. These data were compared with those from a previous Raman and infrared study of adenosine. New marker bands sensitive to the conformational identity of the ribose sugar ring are reported. Plausible assignments of all main spectral bands are suggested by comparison with assignments reported in the literature.

Raman spectra of liquid and solid boron tribromide, BBr 3 , at ambient temperature and at pressures up to 10 GPa are reported. The freezing pressure was determined as 0.38 ± 0.05 GPa. Three fundamental peaks, assigned as librational, bending and stretching modes, were tracked as a function of pressure, and their wavenumbers were fitted to quadratic functions and approached asymptotic values at the highest pressures. The spectra evolved smoothly and there was no evidence of discontinuities associated with structural phase transitions or of major molecular distortions in this pressure range. All modes showed increases in wavenumber with pressure, and that of the lattice mode was appreciable, corresponding to a more than four-fold increase in intermolecular bonding strength at 10 GPa. At high pressures, there was a minor but irreversible colour change of the sample, probably indicative of molecular dissociation and the release of bromine. The results were compared with corresponding data on BI 3 and with those obtained from samples at low temperatures.

Room temperature mid-infrared experiments between 500 and 1800 cm(-1) have been performed on crystalline deoxyadenosine as a function of pressure up to about 10 GPa. Discontinuities observed near 2 and 4 GPa indicate that two separate phase transitions occur at these pressures. Changes in the spectra suggest that both transitions involve a rearrangement of the pucker of the deoxyribose moiety. The wavenumbers of the vibrational modes shift to higher values with applied pressure. Our results for deoxyadenosine are compared to similar measurements on adenosine. Assignments for the observed modes are made on the basis of work published in the literature.