A simple many-fermion system in which there exists N identical fermions in a single spherical orbit with pairing interaction is treated by means of the time-dependent variational approach with a quasi-spin squeezed state with the aim of going beyond the time-dependent Hartree-Fock or Bogoliubov theory. It is shown that the ground state energy is reproduced well analytically in this approach. 1 ...

The form of a real AT-body fermion wave function when expanded in Slater determinants of natural orbitals is investigated using a computer. I t is found that in the case when the number of natural orbitals is N f 2 there is a considerable reduction in the number of Slater determinants required. This offers the possibility of calculating atomic wave functions which are significantly more accurat...

The odd-Z isotope Lr and its daughter Md and grand-daughter Es were studied in two experiments performed at GANIL and the University of Jyväskylä. The Lr nuclei were produced using the cold fusion-evaporation reaction Bi(Ca,2n)Lr at a bombarding energy of 217 MeV. The singleparticle structure and decay properties were investigated using α, γ and electron spectroscopy. The groundstate spin and p...

The Hartree-Fock-Bogoliubov (HFB) equations in coordinate representation are solved exactly, i.e., with correct asymptotic boundary conditions for the continuous spectrum. The calculations are performed with effective Skyrme interactions. The exact HFB solutions are compared with HFB calculations based on box boundary conditions and with resonant continuum Hartree-Fock-BCS (HF-BCS) results. The...

The time dependence of a heavy-ion-atom collision system is solved via a set of coupled channel equations using energy eigenvalues and matrix elements from a self-consistent field relativistic molecular many-electron Dirac-Fock-Slater calculation. Within this independent particle model we give a full many-particle interpretation by performing a small number of single-particle calculations. Firs...

We have investigated the ground and excited state properties of two electron atoms using our Fixed-Phase method, including an analysis of exchange and correlation. We present results of our calculations with a trial phase which corresponds to the atomic Hartree-Fock one.

This article examines the time-dependent Hartree-Fock (TDHF) approximation of single-particle dynamics in systems of interacting fermions. We find the TDHF approximation to be accurate when there are sufficiently many particles and the initial manyparticle state is a Slater determinant, or any Gibbs equilibrium state for noninteracting fermions. Assuming a bounded two-particle interaction, we o...

We describe perturbative methods for improving finite-basis Hartree-Fock calculations toward the complete-basis limit. The best method appears to offer quadratic error reduction and preliminary numerical applications demonstrate that remarkably accurate Hartree-Fock energies can be obtained.

We present an efficient theory and algorithm for computing four-component relativistic Dirac-Fock wave functions using the Coulomb, Gaunt, and full Breit interactions. Our implementation is based on density fitting, and is routinely applicable to systems with 100 atoms and a few heavy elements. The small components are expanded using 2-spinor basis functions. We show that the factorization of 3...