Ab initio total energy study of brucite, diaspore and hypothetical hydrous wadsleyite
學年 83
學期 1
出版(發表)日期 1995-01-01
作品名稱 Ab initio total energy study of brucite, diaspore and hypothetical hydrous wadsleyite
著者 Winkler, B.; Milman, V.; Hennion, B.; Payne, M.C.; 李明憲; Lee, M.H.; Lin, J.S.
單位 淡江大學物理學系
著錄名稱、卷期、頁數 Physics and chemisty of minerals 22(7), pp.461-467
摘要 Ab initio total energy calculations based on the local density approximation (LDA) and the generalised gradient approximation (GGA) of density functional theory have been performed for brucite, Mg(OH)2, diaspore, AlOOH and hypothetical hydrous wadsleyite, Mg7Si4O14(OH)2. The use of a general gradient approximation (GGA) is essential to obtain a good agreement (≈ 1%) of the calculated lattice parameters to diffraction data. The calculated fractional coordinates of brucite and diaspore are in good agreement (≈ 1.5%) with experimental data. The angle of the non-linear hydrogen bond in diaspore is reproduced well, and the calculated Raman active OH stretching frequency in brucite is in very good agreement with spectroscopic data. There are no significant differences between the calculated fractional coordinates and the second derivative of the energy when GGA is used instead of standard LDA. It is concluded that the description of the static and the dynamic behavior of the OH groups in these hydroxides is very good. It is therefore inferred that the parameter free model is predictive and it has been used to evaluate a hypothetical structure of hydrous wadsleyite. The model reproduces the unusual Si-O bond length of 1.7 Å, observed in β-Mg2SiO4. It predicts an O-H distance of 0.97 Å, which is significantly shorter than the distance obtained from earlier model calculations.
語言 en
期刊性質 國內
國別 TWN
出版型式 ,電子版

機構典藏連結 ( http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/72622 )