coupled cluster calculations;
density functional theory;
dissociation energies;
hydrogen bonds;
Monte Carlo methods;
perturbation theory;
van der Waals forces;
water;
GENERALIZED GRADIENT APPROXIMATION;
D O I:
10.1063/1.3193462
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
A recent extensive study has investigated how various exchange-correlation (XC) functionals treat hydrogen bonds in water hexamers and has shown traditional generalized gradient approximation and hybrid functionals used in density-functional (DF) theory to give the wrong dissociation-energy trend of low-lying isomers and van der Waals (vdW) dispersion forces to give key contributions to the dissociation energy. The question raised whether functionals that incorporate vdW forces implicitly into the XC functional predict the correct lowest-energy structure for the water hexamer and yield accurate total dissociation energy is here answered affirmatively for the vdW-DF [M. Dion , Phys. Rev. Lett.92, 246401 (2004)].