Van der Waals density functional calculations of binding in molecular crystals

• A recent paper [J. Chem. Phys. 132 (2010) 134705] illustrated the potential of the van der Waals density functional (vdW-DF) method [Phys. Rev. Lett. 92 (2004) 246401] for efficient first-principle accounts of structure and cohesion in molecular crystals. Since then, modifications of the original vdW-DF version (identified as vdW-DF1) have been proposed, and there is also a new version called vdW-DF2 [Phys. Rev. B 82 (2010) 081101(R)], within the vdW-DF framework. Here we investigate the performance and nature of the modifications and the new version for the binding of a set of simple molecular crystals: hexamine, dodecahedrane, C60, and graphite. These extended systems provide benchmarks for computational methods dealing with sparse matter. We show that a previously documented enhancement of non-local correlations of vdW-DF1 over an asymptotic atom-based account close to and a few A beyond binding separation persists in vdW-DF2. The calculation and analysis of the binding in molecular crystals require appropriate computational tools. In this paper, we also present details on our real-space parallel implementation of the vdW-DF correlation and on the method used to generate asymptotic atom-based pair potentials based on vdW-DF.

Ämnesord

NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

enthalpies

model

Density functional theory

energy

sublimation

C60

accurate

Molecular crystals

surface

x-ray

generalized gradient approximation

vdW-DF

Graphite

Cage molecules

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art (ämneskategori)

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