An ab initio Wannier-function-based approach to electronic groundstate calculations for crystalline solids is outlined. In the framework of the linear combination of atomic orbitals method the infinite character of the solid is rigorously taken into account. The Hartree-Fock groundstate energy, cohesive energy, lattice constant and bulk modulus are calculated in a fully ab initio manner as it i...

The neutron-to-proton density ratio at the nuclear periphery was determined for six targets from the yield of nuclei with mass (At21) generated by antiproton annihilation on targets with mass number At . A new setup allowed us to measure this yield for nuclei with half-lives down to 6 s. The experiment confirmed the negative correlation between the peripheral neutron-to-proton density ratio and...

The structure of in nite nuclear matter is studied with two of the Zimanyi Moszkowski (ZM) models in the framework of a relativistic approximation which takes into account Hartree terms and beyond and is compared with the results which come out of the relativistic Hartree Fock approach in the linear Walecka model. The simple treatment applied to these models can be used in substitution to the m...

This work presents a procedure to optimize the molecular geometry at the Hartree-Fock level, based on a global optimization method—the Generalized Simulated Annealing. The main characteristic of this methodology is that, at least in principle, it enables the mapping of the energy hypersurface as to guarantee the achievement of the absolute minimum. This method does not use expansions of the ene...

The Hartree-Fock equations describe atomic and molecular eletronic wave functions, based on the minimization of a functional of the energy. This can be formulated as a constrained global optimization problem involving nonconvex polynomials exhibiting many local minima. The traditional method of solving the Hartree-Fock problem does not provide a guarantee of global optimality and is very sensit...

The renormalization of a gapless Φ-derivable Hartree–Fock approximation to the O(N)-symmetric λφ theory is considered in the spontaneously broken phase. This kind of approach was proposed by three of us in a previous paper [1] in order to preserve all the desirable features of Φ-derivable DysonSchwinger resummation schemes (i.e., validity of conservation laws and thermodynamic consistency) whil...

The self-energy of the Dirac Brueckner-Hartree-Fock calculation in nuclear matter is parametrized by introducing density-dependent coupling constants of isoscalar mesons in the relativistic Hartree-Fock (RHF) approach where isoscalar meson σ , ω and isovector meson π , ρ contributions are included. The RHF calculations with density dependent coupling constants obtained in this way not only repr...