E. Czuchaj

Semi-local pseudopotential calculations for the adiabatic potentials of alkali-neon systems

Abstract Pseudopotential calculations have been performed to obtain the adiabatic potentials fore the ground state and for several excited states of alkali-neon systems. Both the alkali ion-valence electron and Ne-valence electron interactions are represented by semi-local l-dependent pseudopotentials. Standard variational calculations were made in a basis set of Gaussian functions. The accuracy of the calculated potentials is assessed by comparison with the available experimental data and with results of other calculations. Overall agreement has been obtained. This indicates that a significant improvement in calculations of the adiabatic potentials of alkali-rare gas atoms can be achieved by applying an l -dependent pseudopotential technique.

Adiabatic potential curves for the Cd2 dimer

Abstract Potential energy curves and dipole transition moments for a number of electronic states of the Cd 2 dimer are presented and discussed. They are derived using the MRCI(SD) procedure for the valence electron of the species, while the core electrons are represented by semi-empirical l -dependent pseudopotentials. The effect of spin-orbit coupling is not investigated.

Pseudopotential SCF/CI calculation for the potential energy curves of the CaHe pair

Abstract Potential energy curves for the CaHe system are recalculated using a modified version of the pseudopotential method. Unlike our previous calculations, the CaHe diatomic is now handled as a four-electron system. In the CI calculation, only the valence electrons of Ca are active, whereas the electrons of helium are kept frozen in the ground-state configuration. The calcium core is represented by the semi-empirical l -dependent pseudopotential. Correlation effects due to the rare-gas atom and the Ca-core are accounted for by incorporating the polarization potential into the interaction Hamiltonian. Experimental data on the CaHe collision complex can be fairly well understood in terms of the calculated potentials.

PSEUDOPOTENTIAL CALCULATIONS FOR THE POTENTIAL ENERGIES OF CA+-HE AND CA+-NE

Abstract The pseudopotential treatment used so far for neutral species is extended to the case of the singly charged calcium ion perturbed by helium and neon atoms. The calculations have been performed for the adiabatic potentials and dipole transition moments in dependence on internuclear separation. Spin-orbit coupling is considered in a semi-empirical manner following the ‘atoms-in-molecules’ model. The results are discussed in the context of recent experiments on trapping and laser cooling of Ca + ions in the presence of background gases.

CALCULATION OF GROUND- AND EXCITED-STATE POTENTIAL ENERGY CURVES FOR THE HG2 MOLECULE IN A PSEUDOPOTENTIAL APPROACH

Abstract Potential energy curves for electronic states of the Hg2 dimer are calculated using the SCF and MRCI scheme for the four valence electrons of the system, with the core electrons represented by ab initio quasirelativistic energy adjusted pseudopotentials. Computations are performed for the molecular states that dissociate to the Hg(1S)+Hg(1S, 3P, 1P, 7s3S, 7s1S, 7p3P, 7p1P) asymptotes. The calculated potential curves are split into spin-orbit components in a semiempirical manner following the “atoms-in-molecules” model. Comparison of the derived potentials with known experimental data shows overall good agreement between theory and experiment, although the theoretical potentials are somewhat too shallow.

Semi-local pseudopotential calculations for the potential energies of the CaHe and CaNe systems

Abstract Pseudopotential SCF/CI calculations in a GTO basis set have been performed to obtain the adiabatic potentials for the ground state and for several excited states of the CaHe and CaNe complexes. Semi-empirical l -dependent pseudopotentials are used to describe both the calcium ion-valence electron and rare gas atom-valence electron interaction. The e − -rare gas interaction en-compasses both the dipole and quadrupole terms. Spin-orbit interaction is not included in the calculations. Some direct and indirect relativistic effects on valence-electron orbitals are incorporated via the pseudopotentials. The potentials are presented both diagrammatically and in a tabulated form.

Potential energy curves for the Zn2 dimer

Abstract MRCI(SD) calculations have been performed for the adiabatic potential curves and dipole transition moments of diatomic zinc. Only the four valence electrons of the system are treated explicitly, whereas the atomic cores are replaced by the energy-adjusted pseudopotentials. The spin-orbit coupling has not been considered.

Calculation of the interaction energies for the ZnHg and ZnCd system

Abstract Semi-empirical l -dependent pseudopotentials have been used in the MRCI(SD) calculation of the adiabatic potentials and dipole transition moments for the ZnHg and ZnCd pairs. Only the valence electrons of the system are treated explicitly. The atomic cores are simulated by the energy-adjusted pseudopotentials. The spin—orbit coupling has not been considered.

Use of non-local l-dependent pseudopotentials in the calculation of the potential energies for the Ba-rare gas systems

Abstract Non-local l -dependent pseudopotentials are used in the CI(SD) calculation of the potential energies and dipole transition moments for the Ba-rare gas pairs. The adiabatic potential curves for the ground state and the excited singlet states correlated with the (6s5d) 1 D and (6s6p) 1 P barium terms are calculated without fitting to any experimental data concerning the systems investigated. The effect of spin-orbit coupling has not been considered.

Pseudopotential calculations for the potential energy curves and transition dipole moments of the NaHg system

Abstract Potential energy curves for the ground state and several of the lowest-lying excited states of NaHg have been calculated using the MRSD-Cl procedure for the valence electrons, while all the core electrons are represented by semi-empirical l -dependent pseudopotentials. The effect of spin—orbit coupling has not been investigated. Dipole moments for the transition from the ground to the excited states as a function of internuclear separation have also been calculated.