MOLECULAR-DYNAMICS OF MGSIO3 PEROVSKITE AT HIGH-PRESSURES - EQUATION OF STATE, STRUCTURE, AND MELTING TRANSITION
MOLECULAR-DYNAMICS OF MGSIO3 PEROVSKITE AT HIGH-PRESSURES - EQUATION OF STATE, STRUCTURE, AND MELTING TRANSITION
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DOI：
10.1016/0016-7037(94)90265-8
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发表时间：
1994-10-01
影响因子：
5
通讯作者：
BELONOSHKO, AB
中科院分区：
文献类型：
--
作者：
BELONOSHKO, AB
利用MATSUI（1988）原子间电位对mgsio3 -钙钛矿及其熔体进行了分子动力学（MD）模拟，以解决模型熔化曲线与实验熔化曲线不一致的问题。固体和液体mgsio3 -钙钛矿的状态方程与实验数据一致，有助于在实验无法达到的温度和压力下计算密度。与初步地球模型（DZIEWONSKI和ANDERSON， 1981）的比较表明，mgsio3 -钙钛矿的状态方程与下地幔的地震参数是一致的。在恒压下进行了两相MD模拟，计算出了mgsio3 -钙钛矿的熔化曲线，与最近的实验结果一致。根据有限系统的理论估计，过热不超过400k。根据Simon方程将熔融温度外推到核幔边界压力（134 GPa），得到mgsio3 -钙钛矿的温度约为6400 K，并表明，根据公认的核幔边界温度估计，mgsio3 -钙钛矿保持固体状态。
Molecular dynamics (MD) simulations of MgSiO3-perovskite and melt with the MATSUI (1988) interatomic potential are used to resolve the problem of inconsistency between modeled and experimental melting curves. Equations of state for solid and liquid MgSiO3-perovskite are in agreement with experimental data and are useful for calculating densities at experimentally inaccessible temperatures and pressures. Comparison with the Preliminary Earth Model (DZIEWONSKI and ANDERSON, 1981) shows that the equation of state of MgSiO3-perovskite is consistent with seismic parameter for lower mantle. Two-phase MD simulations at constant pressure were also performed to calculate a melting curve of MgSiO3-perovskite in agreement with the recent experiments. Overheating does not exceed 400 K in accord with the theoretical estimate for finite systems. Extrapolation of meltings temperature to the core-mantle boundary pressure (134 GPa) with the Simon equation gives temperature of approximate to 6400 K for MgSiO3-perovskite and shows that, according to accepted estimates of temperature at core-mantle boundary, MgSiO3-perovskite remains solid.