The thermal expansion at constant pressure of solid CD4 III is calculated for the low temperature region where only the rotational tunneling modes are essential and the effect of phonons and librons can be neglected. It is found that in mK region there is a giant peak of the negative thermal expansion. The height of this peak is comparable or even exceeds the thermal expansion of solid N2, CO, O2 or CH4 in their triple points. It is shown that like in the case of light methane, the effect of pressure is quite unusual: as evidenced from the pressure dependence of the thermodynamic Gr\"{u}neisen parameter (which is negative and large in the absolute value), solid CD4 becomes increasingly quantum with rising pressure.
@article{arxiv.2009.00472,
title = {Negative Thermal Expansion in Solid Deuteromethane},
author = {Yu. A. Freiman and V. V. Vengerovsky and Alexander F. Goncharov},
journal= {arXiv preprint arXiv:2009.00472},
year = {2021}
}
Comments
arXiv admin note: text overlap with arXiv:1911.12655