Pressure-induced structural changes of HBr

First-principles molecular dynamics simulation of solid HBr under pressure has been performed using the Car-Parrinello method. A detailed study of the pressure response of the vibrational and proton-transfer dynamics showed that the phase I can be described as a rotator phase with fluctuating hydrogen bonds up to similar to 10 GPa. We reproduced the shoulder-like structure seen in the infrared spectra of the H-Br stretching mode in the disordered phase. (C) 1999 Published by Elsevier Science B.V. All rights reserved.