Infrared absorption of compressed hydrogen deuteride and calibration of the ruby pressure gauge

The primary subject of this thesis is the study of solid hydrogen deuteride by infrared absorption up to a pressure of 159 GPa and at temperatures ranging from 4 K to 160 K. This work constitutes the first reported infrared study of hydrogen deuteride in the range of ultra-high pressures where phase transitions occur. A phase transition of orientational ordering, previously observed by Raman scattering, is observed with an unusual re-entrant phase line. A phase transition is observed at 157 +/-3 GPa, believed to be the same phase transition that has been observed at a similar pressure in the homonuclear hydrogens, H2 and D2. This is the first reported observation of this phase transition in HD.;The second subject of this thesis is a calibration of the ruby fluorescence pressure gauge, widely used as a means of measuring pressure in ultra-high pressure studies such as the one on HD reported in the first part of this thesis. This work to improve the accuracy of the ruby scale involves first obtaining isothermal equations of state of materials for use as calibration reference curves, and second using these isotherms to calibrate the ruby R-line energy as a function of pressure.