Abstract
The order-disorder phase transition in two-dimensional hydrogen-bonded layers of water molecules in SnCl2·2D2O is remarkable in several respects. It has been shown that the peak in the specific heat is highly symmetric around the phase-transition temperature, and that the crystallographic symmetry of the system does not change. We present neutron-diffraction results which show that the temperature dependence of the hydrogen-site occupancies is also highly symmetric around the phase-transition temperature. These results are discussed in terms of a lattice statistical model which was proposed and solved by Salinas and Nagle. By means of a comparison with the Rhys F model, this model is shown to account for the experimentally observed symmetry properties, although the model is in quantitative disagreement with the experimental data. This comparison also offers a reason for the existence of the peculiar anomaly in the dielectric constant.
Original language | English |
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Journal | Physical Review B |
Volume | 20 |
Issue number | 9 |
Pages (from-to) | 3792-3798 |
ISSN | 2469-9950 |
DOIs | |
Publication status | Published - 1979 |