Rights statement: © 2009 The American Physical Society
Final published version, 164 KB, PDF document
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Quantum Monte Carlo studies of covalent and metallic clusters: accuracy of density functional approximations
AU - Hsing, C. R.
AU - Wei, C. M.
AU - Drummond, Neil
AU - Needs, R. J.
N1 - © 2009 The American Physical Society
PY - 2009/6/1
Y1 - 2009/6/1
N2 - 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.
AB - 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.
U2 - 10.1103/PhysRevB.79.245401
DO - 10.1103/PhysRevB.79.245401
M3 - Journal article
VL - 79
JO - Physical review B
JF - Physical review B
SN - 1550-235X
IS - 24
M1 - 245401
ER -