Abstract
The piston-displacement technique has been used to determine the pressure-volume relations for normal hydrogen () and normal deuterium () at pressures to 25 kbar at 4.2 K. The accuracy of the relative compressions ranges from ± at low pressures to ±3× at 25 kbar. The data, especially for , agree well with earlier 20-kbar results, and the extrapolated bulk moduli, 1.70 ± 0.06 kbar for and 3.15 ± 0.06 kbar for , are consistent with recent ultrasonic data. The shapes of the pressure-volume relations resemble more closely those for the helium isotopes than those for the heavier-rare-gas solids, and suggest that the two-body repulsive interaction for hydrogen molecules (and helium atoms) varies more slowly with intermolecular spacing than that for the heavier-rare-gas atoms. These experiments also give maximum values for the pressure-dependent shear yield stress of solid hydrogen.
- Received 5 August 1974
DOI:https://doi.org/10.1103/PhysRevB.10.5184
©1974 American Physical Society