Investigation of structure and hydrogen bonding of superhydrous phase B (HT) under pressure using first-principles density functional calculations

Poswal, H. K. ; Sharma, Surinder M. ; Sikka, S. K. (2010) Investigation of structure and hydrogen bonding of superhydrous phase B (HT) under pressure using first-principles density functional calculations High Pressure Research, 30 (1). pp. 198-206. ISSN 0895-7959

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Related URL: http://dx.doi.org/10.1080/08957950903503920

Abstract

High-pressure behaviour of superhydrous phase B (high temperature; HT) of Mg10Si3O14(OH)4 (Shy B) is investigated with the help of density functional theory-based first-principles calculations. In addition to the lattice parameters and equation of state, we use these calculations to determine the positional parameters of atoms as a function of pressure. Our results show that the compression induced structural changes involve cooperative distortions in the full geometry of the hydrogen bonds. The bond-bending mechanism proposed by Hofmeister et al. (Vibrational spectra of dense hydrous magnesium silicates at high pressure: Importance of the hydrogen bond angle, Am. Miner. 84 (1999), pp. 454-464) for hydrogen bonds to relieve the heightened repulsion due to short H---H contacts is not found to be effective in Shy B. The calculated O-H bond contraction is consistent with the observed blue shift in the stretching frequency of the hydrogen bond. These results establish that one can use first-principles calculations to obtain reliable insights into the pressure-induced bonding changes of complex minerals.

Item Type:Article
Source:Copyright of this article belongs to Taylor and Francis Ltd.
Keywords:DFT Calculations; Superhydrous Phase B; Hydrogen Bonding
ID Code:48212
Deposited On:14 Jul 2011 08:33
Last Modified:18 May 2016 03:30

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