A relativistic pseudopotentional (RPP) for use in ab initio molecular electronic structure calculations is derived in the context of the relativistic effective core potential (REP) method of Lee et al. The resulting atom-specific RPP has salient features of the REP imbedded within it while retaining the form of a functional that is dynamically defined at runtime when used in calculations on mol...

The coupled cluster based linear response theory which is applicable to the direct calculation of atomic and molecular properties are presented and applied to compute the ionization potentials and excitation energies of light and moderately heavy atoms. The effect of electron correlation on the ground and excited states is studied using Hartree-Fock, Dirac-Fock and approximate two-component rel...

We study the energy of relativistic electrons and positrons interacting via the second quantized Coulomb potential in the field of a nucleus of charge Z within the Hartree-Fock approximation. We show that the associated functional has a minimizer. In addition, all minimizers are purely electronic states, they are projections, and fulfill the no-pair Dirac-Fock equations.

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...