Lindemann melting law: anharmonic correction and test of its validity for minerals.

High-P experimental data are used to evaluate the validity of the Lindemann melting criterion for minerals. Because anharmonicity can be significant at the high T associated with melting, leading order arharmonic contributions to the mean-square atomic vibrations have been included in the present lattice dynamical formulation of the Lindemann criterion. In general, although atomic vibrations can be significantly anharmonic near the melting point, the shape of the melting curve predicted from the Lindemann criterion is not much influenced by anharmonicity. The Lindemann expression is inconsistent with experimental melting data for a variety of substances, particularly at low P. In general, a Lindemann criterion is not an adequate description of the melting behaviour of minerals. Therefore, an application of the Lindemann law to obtain the melting T of minerals at high P, and to determine the fusion curve of the Earth's deep interior is, at present, speculative.-A.W.H.