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论文类型： 期刊论文

发表时间： 2008-09-15

发表刊物： COMPUTER PHYSICS COMMUNICATIONS

收录刊物： SCIE、EI、Scopus

卷号： 179

期号： 6

页面范围： 417-423

ISSN号： 0010-4655

关键字： first-principles; forsterite; phase transition; high pressure; quasi-harmonic Debye model

摘要： The high-pressure and/or high-temperature behavior and alpha/beta phase transition of forsterite (Mg2SiO4) were investigated by first principle calculations: local density approximation (LDA). generalized gradient approximation (GGA) and the quasi-harmonic Debye model in consideration of the temperature effect. At zero pressure and zero temperature, the calculated values of lattice parameters and elastic constants are well concordant with experimental data. The calculated values of cell volume at different pressures and temperatures are compatible with experiments. The results calculated by LDA are more concordant with the experimental results than those by GGA for describing Mg(2)SA crystals. The boundaries of the P-T plots for phase transition are calculated to be 0.00779 GPa/K by LDA and 0.00772 GPa/K by GGA. suggesting the upper and lower limits of the phase boundary for alpha/beta forsterite. At temperature of less than 1000 K, the calculated results agree reasonably with experimental ones. Thus, the present results indicate that combination of first-principles and quasi-harmonic Debye model is an efficient approach to simulate the behavior of minerals at high pressure and/or high temperature. (C) 2008 Elsevier B.V. All rights reserved.