Elastic properties of hydrous forsterite under high pressure: first-principles calculations
Elastic and electronic properties of anhydrous (Mg2SiO4) and hydrous forsterite crystals with 3.2wt %(Mg1.75H0.5SiO4) and 1.6wt% water (Mg1.875H0.25SiO4) under high pressure were investigated using firstprinciple calculations within local density approximation. Different hydrogen locations around the Mg cation vacancy (as structurally bound OH) have been compared in terms of total energy and elastic properties. Comparison of the anhydrous and hydrous forsterite crystals shows that hydration reduces the mass density, elastic moduli, and sound velocities. Adding 3.2wt % and 1.6wt% water leads to reductions of compressional and shear wave velocities (VP and VS) of forsterite by 3.1%-7.1% and 3.6%-9.7%, and by 2.4%-4.1% and 3.3%-6.6% at pressures from 0 GPa to 14 GPa, respectively. The reduction of sound velocity of hydrous forsterite decreases with water content. This may be the main reason for formation of the low velocity zones in the Earth mantle. However, substitution of hydrogen with Mgcation in forsterite has little effect on its electronic state. The band gap of hydrous forsterite crystals is comparable to the gap of anhydrous one and slightly increases with increasing pressure.
Lei Liu Jianguo Du Jijun Zhao Hong Liu Haili Gao Yuxiang Chen
Institute of Earthquake science, China Earthquake Administration, Beijing 100036, China School of Physics and Optoelectronic Technology and College of Advanced Science and Technology, Dali Institute of Earthquake science, China Earthquake Administration, Beijing 100036, China Institute of
国际会议
武汉
英文
657-690
2010-09-01（万方平台首次上网日期，不代表论文的发表时间）