LOW-TEMPERATURE HEAT CAPACITIES OF SOLID ARGON AND KRYPTON

The specific heats of high-purity argon and krypton have been measured between 0.4 and 12°K, permitting a reliable extrapolation to 0°K. The higher-temperature results are in agreement with those of Morrison et al., but for argon the extrapolation to 0°K is not. At the lowest temperatures the heat capacities are represented by C=(125)π4R(TΘ0)3, with Θ0=92.0 °K for argon and 71.9°K for krypton. The apparatus and techniques are described, and the results are compared with theoretical estimates. © 1969 The American Physical Society.