Low-Temperature Speed of Sound in Single-Crystal Ice

Abstract

Only one of the previous measurements of the elastic constants and speed of sound in single‐crystal ice I had been extended below −30°C. All of the five independent elastic constants have now been measured down to 65°K. Elastic‐constant data have been fitted to second‐degree polynomials. From these polynomials, a 0°K value for the c_ij's is extracted and a Debye characteristic temperature of 224°K is calculated. This Debye temperature compares favorably with that previously computed from heat‐capacity data. No sudden changes in the pseudoelastic anisotropic factor c₃₃/c₁₁ are found to take place at 190°K, as had been previously reported.