Neon impurity effects in the specific heat of solid D2

Abstract

Measurements have been made of the specific heat of solid deuterium with neon impurity concentrations of between 1 and 4 %. In addition, the para-D2 concentration of the samples studied has been varied between 0.9 and 6%. An excess specific heat A C was observed above approximately 1.4 K which was proportional to the Ne concentration and independent of the para-D2 concentration. AC is attributed to resonance modes involving the heavy neon atoms randomly distributed throughout the host lattice. The values of AC are qualitatively in general agreement with classical theory, with the quantitative differences due to the quantum nature of the solid.