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arXiv · 1104.1784

Van der Waals interactions in the ground state of Mg(BH4)2 from density functional theory

A. Bil·B. Kolb·R. Atkinson·D. G. Pettifor·T. Thonhauser·A. N. Kolmogorov
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Abstract

In order to resolve an outstanding discrepancy between experiment and theory regarding the ground-state structure of Mg(BH4)2, we examine the importance of long-range dispersive interactions on the compound's thermodynamic stability. Careful treatment of the correlation effects within a recently developed nonlocal van der Waals density functional (vdW-DF) leads to a good agreement with experiment, favoring the α-Mg(BH4)2 phase (P6122) and a closely related Mn(BH4)2-prototype phase (P3112) over a large set of polymorphs at low temperatures. Our study demonstrates the need to go beyond (semi)local density functional approximations for a reliable description of crystalline high-valent metal borohydrides.

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A. Bil, B. Kolb, R. Atkinson, D. G. Pettifor, T. Thonhauser, A. N. Kolmogorov. 2011-04-10. Van der Waals interactions in the ground state of Mg(BH4)2 from density functional theory. https://doi.org/10.1103/physrevb.83.224103

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