Vibron effective charges in dense hydrogen

Abstract
We report quantitative intensity measurements of the infrared vibron in the high-pressure molecular phase of solid hydrogen above 150 GPa. The results are analyzed in terms of effective static and dynamic charge. The effective charge reaches 0.04e at 230 GPa, which rules out full ionization of the hydrogen molecules to these pressures. The results are consistent with charge transfer associated with orientational ordering in this phase.