The accuracy of the Hartree-Fock method with an empirical dispersion correction, HF-D3, to model interaction energies and locate constrained minimum geometries is tested against more conventional correlation methods, such as second-order perturbation theory and coupled cluster theory, and against the sophisticated effective fragment potential model. HF-D3 was applied to substituted-benzene dime...

The HF/3s2pld and MP213s2pld structures, energies and vibrational frequencies were calculated for ten N8 isomers, corresponding to ten analogous CH structures. Comparative calculations using density functional theory (DFT), with a cc-pVTZ basis set, were also performed. All ten structures were found to be local minima on the energy hypersurface at the Hartree-Fock (HF) level, whereas at the sec...

We develop a time-dependent Gutzwiller approximation (GA) for the Hubbard model analogous to the time-dependent Hartree-Fock (HF) method. This new formalism incorporates ground state correlations of the random phase approximation (RPA) type beyond the GA. Static quantities like ground state energy and double occupancy are in excellent agreement with exact results in one dimension up to moderate...

The Coupled Perturbed Hartree-Fock (CPHF) scheme recently implemented in the CRYSTAL06 code for systems periodic in 1-3 dimensions has been generalized to Density Functional Hamiltonians (CPKS, Coupled Perturbed Kohn-Sham). The dielectric tensor of Magnesium Oxide, Diamond, and Silicon is calculated with four different Hamiltonians, ranging from DFT, in the local density and gradient corrected ...

The effective fragment potential (EFP) method, is a discrete method for the treatment of solvent effects, originally formulated using Hartree–Fock (HF) theory. Here, a density functional theory(DFT) based implementation of the EFP method is presented for water as a solvent. In developing the DFT based EFP method for water, all molecular properties (multipole moments, polarizabilitytensors, scre...

We study the quasiparticle band structure of isolated, infinite (HF)(infinity) and (HCl)(infinity) bent (zigzag) chains and examine the effect of the crystal field on the energy levels of the constituent monomers. The chains are one of the simplest but realistic models of the corresponding three-dimensional crystalline solids. To describe the isolated monomers and the chains, we set out from th...

The kernel energy method (KEM) is applied to the vesicular stomatitis virus (VSV) nucleoprotein (PDB ID code 2QVJ). The calculations employ atomic coordinates from the crystal structure at 2.8-A resolution, except for the hydrogen atoms, whose positions were modeled by using the computer program HYPERCHEM. The calculated KEM ab initio limited basis Hartree-Fock energy for the full 33,175 atom m...

We develop a general theory to describe a superconducting Fermion system with large quantum fluctuations. The theory is a direct extension of the resonating Hartree-Fock (HF) theory to the Hartree·Bogoliubov case including pair correlations. We start with an exact coherent state representation of a superconducting Fermion system on 'a special orthogonal group. A state with large quantum fluctua...