Structure and spectroscopic properties of dense solid hydrogen at 160 GPa

The structure and spectroscopic properties of dense solid hydrogen structures are re-examined. The objective was to critically examine several candidate structures including the structure with space group C2/c recently proposed by Pickard and Needs. All of these have a unique similar structural feature and their spectroscopic properties such as high infrared intensity agree with experimental findings near 160 GPa. The Raman and infrared spectra as well as the detailed phonon stability of the C2/c structure are examined. The pressure dependence of the infrared absorption intensity is shown to be in excellent agreement with experiment. Crown Copyright (C) 2007 Published by Elsevier Ltd. All rights reserved.