Pressure-tuning infrared and Raman spectroscopy of Group 14 tetraphenyl compounds

The effect of high external pressures on the vibrational spectra of the tet raphenyl Group 14 compounds, Ph4M (M = Si, Ge, Sn, Pb), were examined betwe en ambient pressure and 40 kbar with the aid of a diamond-anvil cell. The f our compounds displayed similar behaviour as the pressure was increased and a structural transition at similar to 15 kbar, most probably associated wi th a phenyl ring rotation, was identified in each case. The pressure depend encies of selected vibrational modes were obtained. (C) 2000 Elsevier Scien ce B.V. All rights reserved.