the molecular geometry of complex of adenine with 8 water molecules was calculated with hartree-fock (hf). the standard 6-31g(d) basis set has been employed. the existence of c-h…o hydrogen bonds between the water molecules and the hydrophobic part of nucleobase is stablished. we optimized structures and computed interaction energies of all complexes of adenine with water molecules step by step...

We give a brief discussion of the recently developed Constrained-Path Monte Carlo Method. This method is a quantum Monte Carlo technique that eliminates the fermion sign problem plaguing simulations of systems of interacting electrons. The elimination is accomplished by trading an exact procedure for an approximate one that has been demonstrated to give very accurate estimates of energies and m...

Hartree-Fock exchange with a truncated Coulomb operator has recently been discussed in the context of periodic plane-waves calculations [Spencer, J.; Alavi, A. Phys. Rev. B: Solid State, 2008, 77, 193110]. In this work, this approach is extended to Gaussian basis sets, leading to a stable and accurate procedure for evaluating Hartree-Fock exchange at the Γ-point. Furthermore, it has been found ...

We investigated self-consistent spin-resolved local-field corrections in a spin-polarized electron gas. The local-field corrections, structure factors, and susceptibility functions form a self-consistent loop. Three different local-field corrections and structure factors each based on the Hartree-Fock structure factor, the Gori-Giorgi–Perdew pair correlation function, and self-consistent calcul...

We show how the linear delta expansion, as applied to the slow-roll transition in quantum mechanics, can be recast in the closed time-path formalism. This results in simpler, explicit expressions than were obtained in the Schrödinger formulation and allows for a straightforward generalization to higher dimensions. Motivated by the success of the method in the quantummechanical problem, where it...

The charge renormalization procedure for the calculation of the correlation energy of atoms utilizing the analytically known large-D limit solutions for the exact and Hartree–Fock equations is extended to diatomic molecules. This procedure is based on the variation of the nuclear charge, Z , and internuclear distance, R , of the Hartree–Fock Hamiltonian such that the Hartree–Fock energy will be...

For an infinite system of nucleons interacting through a central spin-isospin schematic force we discuss how the Hartree-Fock theory at finite temperature T yields back, in the T = 0 limit, the standard zero-temperature Feynman theory when there is no symmetry breaking. The attention is focused on the mechanism of cancellation of the higher order Hartree-Fock diagrams and on the dependence of t...

Effects of the relativistic correction Coulomb interaction on doubly-magic nuclei are discussed with Skyrme Hartree--Fock calculations. The is treated by using local density approximation. It found that to total energy about $ 2.4 \, \mathrm{MeV} for {}^{208} \mathrm{Pb} $, while proton and neutron radii do not change significantly. This difference larger than exchange (Fock) calculated (Hartre...

In this paper, the Hartree-Fock equations are proved to be the non relativistic limit of the Dirac-Fock equations as far as convergence of \stationary states" is concerned. This property is used to derive a meaningful deenition of \ground state" energy and \ground state" solutions for the Dirac-Fock model.

The pairing properties of nuclear systems are a sensitive probe of the effective nucleon-nucleon interactions. We compare the 1 S 0 pairing gaps in nuclear and neutron matter derived from the phenomenological Gogny interaction and a renormal-ization group motivated low-momentum V low k interaction extracted from realistic interactions. We find that the pairing gaps predicted by these interactio...