P‐V‐T equation of state of cubic CaSiO3 perovskite from first‐principles computation
P‐V‐T equation of state of cubic CaSiO3 perovskite from first‐principles computation
复制标题
DOI：
10.1002/2013jb010905
复制
发表时间：
2014-04
期刊：
影响因子：
--
通讯作者：
K. Kawai;T. Tsuchiya
中科院分区：
文献类型：
--
作者：
K. Kawai;T. Tsuchiya
钙钛矿（Pv）被认为是地球下地幔（LM）中最丰富的矿物之一，在LM压力和温度下具有理想的立方结构。在这项研究中，压力-体积-温度（P-V-T）状态方程模型的Ca-Pv的构造使用密度泛函第一性原理分子动力学模拟。计算的P-V-T数据得出KT 01000 K = 203.95 GPa，V01000 K = 46.17 μ 3/公式单位，γ0 = 1.576，q = 0.96，符合Mie-Grüneisen-Debye公式。我们比较了Ca-Pv的密度和体积声速与含铁Mg-Pv和地震学值。沿着绝热温度梯度，Ca-Pv的密度比初始参考地球模型高约2.5%，体声速比初始参考地球模型快约0.7%，而它的密度比含铁Mg-Pv高约3.8%，体声速比含铁Mg-Pv慢约2.7%。我们的结果表明，LM中Ca-Pv分数的可能横向变化可以在VΦ和ρ之间产生一种近似关系。
Ca‐perovskite (Pv) is considered to be one of the most abundant minerals in the Earth's lower mantle (LM) with an ideal cubic structure at LM pressures and temperatures. In this study, a pressure‐volume‐temperature (P‐V‐T) equation of state model for Ca‐Pv is constructed using density functional first‐principles molecular dynamics simulations. The calculated P‐V‐T data yield KT01000K = 203.95 GPa, V01000K = 46.17 Å3/formula unit, γ0 = 1.576, and q = 0.96 within the framework of the Mie–Grüneisen–Debye formulation. We compare the density and bulk sound velocity of Ca‐Pv with those of iron‐bearing Mg‐Pv and seismological values. Along an adiabatic temperature gradient, Ca‐Pv has ~2.5% higher density and ~0.7% faster bulk sound velocity than the preliminary reference Earth model, while it has ~3.8% higher density and ~2.7% slower bulk sound velocity than iron‐bearing Mg‐Pv. Our results indicate that a possible lateral variation in the Ca‐Pv fraction in the LM could produce an anticorrelation between VΦ and ρ.