The compressibility and high pressure structure of diopside from first principles simulation
The compressibility and high pressure structure of diopside from first principles simulation
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DOI：
10.1007/s00269-008-0229-3
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发表时间：
2008-03
影响因子：
1.4
通讯作者：
A. Walker;Rick Tyer;R. Bruin;M. Dove
中科院分区：
文献类型：
--
作者：
A. Walker;Rick Tyer;R. Bruin;M. Dove
采用密度泛函理论的平面波和赝势方法计算了透辉石（CaMgSi 2 O 6）在0 ~ 25 GPa压力下的结构.在应用4.66 GPa的压力校正以允许通常与广义梯度近似相关联的欠结合之后，细胞参数与实验良好一致。拟合到三阶Birch-Murnaghan状态方程，体积模量和压力导数的值分别为122 GPa和4.7。除了细胞参数，我们的计算提供了所有的原子位置参数的压力远远超出目前可从实验。我们分析了这些数据的多面体的刚度和规则性，并发现，最可压缩的钙多面体变得明显低于各向异性10 GPa以上。
The structure of diopside (CaMgSi2O6) has been calculated at pressures between 0 and 25 GPa using the planewaves and pseudopotentials approach to density functional theory. After applying a pressure correction of 4.66 GPa to allow for the under-binding usually associated with the generalized gradient approximation, cell parameters are in good agreement with experiment. Fitting to the third-order Birch–Murnaghan equation of state yields values of 122 GPa and 4.7 for the bulk modulus and its pressure derivative. In addition to cell parameters, our calculations provide all atomic positional parameters to pressures considerably beyond those currently available from experiment. We have analyzed these data in terms of polyhedral rigidity and regularity and find that the most compressible Ca polyhedron becomes markedly less anisotropic above 10 GPa.