Quantum Monte Carlo studies of covalent and metallic clusters: accuracy of density functional approximations

Hsing, C. R. and Wei, C. M. and Drummond, Neil and Needs, R. J. (2009) Quantum Monte Carlo studies of covalent and metallic clusters: accuracy of density functional approximations. Physical review B, 79 (24). ISSN 1550-235X

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Abstract

To assess the accuracy of exchange-correlation approximations within density functional theory (DFT), diffusion quantum Monte Carlo (DMC) and DFT methods are used to calculate the energies of isomers of three covalently bonded carbon and boron clusters (C20, B18, and B20), and three metallic aluminum and copper clusters (Al13, Al55, and Cu13). We find that local and semilocal DFT methods predict the same energy ordering as DMC for the metallic clusters but not for the covalent clusters, implying that the DFT functionals are inadequate in such systems. In addition, we find that DFT fails to describe energy reductions arising from Jahn-Teller distortions.

Item Type:
Journal Article
Journal or Publication Title:
Physical review B
Additional Information:
© 2009 The American Physical Society
Uncontrolled Keywords:
/dk/atira/pure/researchoutput/libraryofcongress/qc
Subjects:
ID Code:
55599
Deposited By:
Deposited On:
10 Jul 2012 08:09
Refereed?:
Yes
Published?:
Published
Last Modified:
14 Jul 2020 03:12