We report all-electron variational and diffusion quantum Monte Carlo (VMC and DMC) calculations for the noble gas atoms He, Ne, Ar, Kr, and Xe. The calculations were performed using Slater-Jastrow wave functions with Hartree-Fock single-particle orbitals. The quality of both the optimized Jastrow factors and the nodal surfaces of the wave functions declines with increasing atomic number Z, but ...

Energy levels, wavelengths and radiative decay rates have been calculated for states within the 4pk (k = 1–5) and 4dk (k = 1–9) ground configurations in highly charged tungsten ions. Magnetic dipole (M1) and electric quadrupole (E2) transition probabilities have been obtained using the fully relativistic multiconfiguration Dirac–Fock (MCDF) approach including the correlations within the n = 4 c...

The authors present scalar-relativistic energy-consistent Hartree-Fock pseudopotentials for the main-group elements. The pseudopotentials do not exhibit a singularity at the nucleus and are therefore suitable for quantum Monte Carlo (QMC) calculations. They demonstrate their transferability through extensive benchmark calculations of atomic excitation spectra as well as molecular properties. In...

We present and discuss the results of calculations of the CaF2 bulk and surface electronic structure. These are based on the ab initio Hartree–Fock (HF) method with electron correlation corrections and on Density Functional Theory (DFT) calculations with different exchange-correlation functionals, including hybrid exchange techniques. Both approaches use the localised Gaussian-type basis set. A...

We have developed a quantum Monte Carlo application for the computation of energy eigenvalues for atoms and ions in strong magnetic fields. We use guiding wave functions obtained by Hartree-Fock-Rothaan calculations. For these calculations, we use previously published code C. Schimeczek, D. Engel, G. Wunner, Comp. Phys. Comm. 183, 1502 – 1510 (2012)], as well as the recently developed 2DLHFR me...

The elastic low-energy positron scattering on Be, Mg, Ca, Sr, Ba and Ra atoms has been investigated at energies below 100 eV. The ab initio calculated polarization potentials applied in these calculations were obtained by solving the coupled Dirac-Hartree-Fock equations. Comparison between present results and those of previous model calculations shows serious discrepancies. Particularly, we do ...

Hartree-Fock calculations with the SKX Skyrme interaction are carried out to obtain a-decay Q values for deformed nuclei above Pb assuming axial symmetry. The results for even-even nuclei are compared with the experiment and with the previous calculations. Predictions are made for a-decay Q values and half-lives of even-even superheavy nuclei. The results are also compared for the recently disc...

Generalized Relativistic Effective Core Potential (GRECP) calculation of spectroscopic constants for the HgH molecule and its ions is carried out with the help of Fock-space Relativistic Coupled Cluster method with Single and Double cluster amplitudes (RCC-SD). The calculated spectroscopic constants are compared with experimental data and results of calculations of other groups. Errors of the p...

It is well-known that the Random Phase Approximation (RPA) is equivalent to Time-Dependent Hartree-Fock (TDHF) to first order in the density fluctuations from the static Hartree-Fock ground state. Therefore either approach may be used to calculate giant resonance states in nuclei. Historically, the RPA approach has been more popular, particularly working directly in the response function formal...