Quantum-thermodynamic treatment of intrinsic anharmonicity; Wallace’s theorem revisited

Autor: Michel H.G. Jacobs, Bernard H.W.S. de Jong
Rok vydání: 2005
Předmět:
Zdroj: Physics and Chemistry of Minerals. 32:614-626
ISSN: 1432-2021
0342-1791
DOI: 10.1007/s00269-005-0038-x
Popis: Wallace (in Thermodynamics of crystals, 1972) developed a theorem, rooted in rigid lattice dynamics, which incorporates intrinsic anharmonic effects in solids. The practical application of this theorem in mineral physics is computationally involved and this is the main reason for the theorem not getting the attention it deserves. Because intrinsic anharmonicity is an important issue at the extreme conditions in planetary mantles, we derived a method which removes the computational obstacles in applying this theorem. We extended the theorem to incorporate details of the phonon spectrum and tested our algorithm on forsterite (Mg2SiO4). Using a least squares inversion technique applied to all available experimental data, we show that it results in an accurate representation of thermodynamic properties and sound wave velocities of Mg2SiO4 in its complete pressure–temperature stability range. We also show that the accuracy of our results is not significantly affected by the use of a different equation of state.
Databáze: OpenAIRE
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