We report on numerical studies of the influence of Coulomb interactions on localization of electronic wavefunctions in a strong magnetic field. Interactions are treated in the Hartree-Fock approximation. Localization properties are studied both by evaluating participation ratios of Hartree-Fock eigenfunc-tions and by studying the boundary-condition dependence of Hartree-Fock eigenvalues. We fin...

Comparison is made between a combined quantum mechanics/interatomic potential function approach ~QM-Pot! and its fully quantum-mechanical limit, ab initio calculation applying periodic boundary conditions. The Hartree–Fock ~HF! method is combined with ab initio-parametrized ion pair shell model potential functions. The CRYSTAL code is employed for the periodic Hartree–Fock calculations. The sam...

A linear regression correction approach has been developed successfully to account for the electron correlation energy missing in Hartree-Fock calculation and to reduce the calculation errors of density functional theory. The numbers of lone-pair electrons, bonding electrons and inner layer electrons in molecules, and the number of unpaired electrons in the composing atoms in their ground state...

The Hartree-Fock states of the many-electron atomic system can be unstable with respect to a static or dynamic shift of the electron shells. An appropriate non-rigid shell model for atomic clusters is developed. It permits to formulate a convenient approach to the semiempirical description of the different correlation effects and to reveal some new effects. In the framework of conventional Hart...

Abstract The ability of the Gogny forces D1 family to describe nucleon-nucleus scattering is studied. To this end, we use an optical model (OM) potential built up using a semi-microscopic nuclear matter (NM) approach. real and imaginary parts OM are provided by first second-order terms, respectively, Taylor expansion mass operator calculated within Brueckner–Hartree–Fock (BHF) method reaction G...

It is well-known that in bulk, the solution of the Bogoliubov-de Gennes equations is the same whether or not the Hartree-Fock term is included. In this case the Hartree-Fock potential is position independent and, so, gives the same contribution to both the single-electron energies and the Fermi level (the chemical potential). Thus, the single-electron energy measured from the Fermi level (it co...

We assess a variant of linear-response range-separated time-dependent density-functional theory (TDDFT), combining a long-range Hartree-Fock (HF) exchange kernel with a short-range adiabatic exchange-correlation kernel in the local-density approximation (LDA) for calculating isotropic C6 dispersion coefficients of homodimers of a number of closed-shell atoms and small molecules. This range-sepa...

A linear regression correction approach has been developed successfully to account for the electron correlation energy missing in Hartree–Fock calculation and to reduce the calculation errors of density functional theory. The numbers of lone-pair electrons, bonding electrons and inner layer electrons in molecules, and the number of unpaired electrons in the composing atoms in their ground state...

The Fourier transform infrared spectra (FT-IR) and Fourier transform Raman spectra (FT Raman) of The 1-Propyl 4-Piperidone have been recorded in the regions 4000-400, 4000-100 cm -1 . The ultraviolet spectra (UV) spectra of the title molecule in the region 800-200 cm -1 . Utilizing the observed FT-IR and FT Raman spectra data, a complete vibrational assignments and analysis of the fundamental m...

nowadays nmr spectroscopy becomes a powerful tool in chemistry because of the nmr chemical shifts. hartree–fock theory and the gauge-including atomic orbital (giao) methods are used in the calculation of 29si nmr chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. calculations have been performed at geo...