High-Pressure Measurements of Hydrogen Phase IV Using Synchrotron Infrared Spectroscopy

Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, DC 20015, USA(Received 24 December 2012; published 21 May 2013)Phase IV of dense solid hydrogen has been identified by its infrared spectrum using high-pressuresynchrotron radiation techniques. The spectrum exhibits a sharp vibron band at higher frequency andlower intensity than that for phase III, indicating the stability of molecular H