Experimental and theoretical thermal equations of state of MgSiO3 post-perovskite at multi-megabar pressures.
Experimental and theoretical thermal equations of state of MgSiO3 post-perovskite at multi-megabar pressures.
复制标题
DOI：
10.1038/srep22652
复制
发表时间：
2016-03-07
影响因子：
4.6
通讯作者：
Hirao N
中科院分区：
文献类型：
--
作者：
Sakai T;Dekura H;Hirao N
MgSiO3后钙钛矿相是超级地球地幔中最丰富的硅酸盐相，尽管它只存在于地球的最低地幔中。在这项研究中，我们建立了热状态方程（EoS）的MgSiO3后钙钛矿相，这是通过使用激光加热金刚石对顶砧单元和密度泛函理论技术，在一个多兆巴的压力范围内，对应于一个超级地球的地幔的条件。首次采用Keane和AP 2 EoS模型提取有意义的物理特性。实验确定的Grüneisen参数，这是一个热EoS参数，其体积依赖性被发现是一致的，与他们的理论获得的值。这减少了先前报道的实验和理论之间的差异。实验和理论EoS也被发现是在非常好的协议，在压力和温度高达300 GPa和5000 K，分别为体积。我们新开发的EoS应该适用于一个超级地球的地幔，以及地球的核幔边界区。
The MgSiO3 post-perovskite phase is the most abundant silicate phase in a super-Earth’s mantle, although it only exists within the Earth’s lowermost mantle. In this study, we established the thermal equation of state (EoS) of the MgSiO3 post-perovskite phase, which were determined by using both laser-heated diamond anvil cell and density-functional theoretical techniques, within a multi-megabar pressure range, corresponding to the conditions of a super-Earth’s mantle. The Keane and AP2 EoS models were adopted for the first time to extract meaningful physical properties. The experimentally determined Grüneisen parameter, which is one of the thermal EoS parameters, and its volume dependence were found to be consistent with their theoretically obtained values. This reduced the previously reported discrepancy observed between experiment and theory. Both the experimental and theoretical EoS were also found to be in very good agreement for volumes at pressures and temperatures of up to 300 GPa and 5000 K, respectively. Our newly developed EoS should be applicable to a super-Earth’s mantle, as well as the Earth’s core-mantle boundary region.