LOW-TEMPERATURE HEAT-CAPACITY, DIELECTRIC-CONSTANT, AND THERMODYNAMIC PROPERTIES OF SOLID GERMANE

The heat capacity of solid germane, GeH4, has been measured over the range 2.8 K < T < 111 K with an estimated precision of ±1%, except below 5 K where it becomes ±2%. Substantial differences between our data and those of Clusius and Faber [Z. Phys. Chem. Abt. B 51, 352(1942)] occur in the region of overlap. Analysis of our data shows the presence of a residual entropy of R ln 1.6 and the presence of a nonvibrational contribution to Cp at T < 5 K. Present is an AT-2 term in the C p beginning around 4 K which is consistent with the Schottky-type anomaly, suggesting the possibility of conversion of the spin species. Our analysis also shows the translational and librational branches of the frequency spectrum are separated with the latter modes becomes fully excited at 60 K. The dielectric constant ε of GeH4 has been measured over the range 4.2 K < T < 141 K with an estimated precision of ±1%. Density of solid GeH4 has been measured at temperatures of liquid nitrogen and of liquid air. © 1978 American Institute of Physics.