A computational method, based on the quasiharmonic approximation, has been computer-coded to calculate the temperature dependence of elastic constants and structural features of crystals. The model is applied to calcite, CaCO3; an interatomic potential based on a C-O Morse function and Ca-O and O-O Born-type interactions, including a shell model for O, has been used. Equilibrations in the range 300-800 K reproduce the experimental unit-cell edges and bond lengths within 1%. The simulated thermal expansion coefficients are 22.3 (//c) and 2.6 (⊥c), against 25.5 and -3.7×10-6K-1 experimental values, respectively. The thermal coefficients of elastic constants tend to be underestimated; for the bulk modulus, -2.3 against -3.7×10-4K-1 is obtained.
Modelling of the thermal dependence of structural and elastic properties in calcite (CaCO3) / A. Pavese, M. Catti, S. Parker, A. Walls. - In: PHYSICS AND CHEMISTRY OF MINERALS. - ISSN 0342-1791. - 23:2(1996), pp. 89-93. [10.1007/BF00202303]
Modelling of the thermal dependence of structural and elastic properties in calcite (CaCO3)
A. PavesePrimo
;
1996
Abstract
A computational method, based on the quasiharmonic approximation, has been computer-coded to calculate the temperature dependence of elastic constants and structural features of crystals. The model is applied to calcite, CaCO3; an interatomic potential based on a C-O Morse function and Ca-O and O-O Born-type interactions, including a shell model for O, has been used. Equilibrations in the range 300-800 K reproduce the experimental unit-cell edges and bond lengths within 1%. The simulated thermal expansion coefficients are 22.3 (//c) and 2.6 (⊥c), against 25.5 and -3.7×10-6K-1 experimental values, respectively. The thermal coefficients of elastic constants tend to be underestimated; for the bulk modulus, -2.3 against -3.7×10-4K-1 is obtained.
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