TY - JOUR

T1 - Multiconfiguration Calculations of the Electron Structure of Ag2 and Ag+2 with the Aid of the Effective Core Potential

T2 - II. Spectroscopic Constants and Low-Lying Electronic States

AU - Kuznetsov, V. G.

AU - Abarenkov, I. V.

AU - Batuev, V. A.

AU - Titov, A. V.

AU - Tupitsyn, I. I.

AU - Mosyagin, N. S.

PY - 1999/12

Y1 - 1999/12

N2 - Ab initio calculations of spectroscopic constants and low-lying electronic states of Ag2 and Ag+2 dimers are reported. They are made by the Hartree-Fock (HF) method and the restricted active space self-consistent field (RASSCF) method with the aid of semilocal nonrelativistic and relativistic 11-electron effective core potentials (ECP and RECP). To find the quality of the potential constructed in this way, we made nonrelativistic calculations by the HF method of the Ag2 molecule, both all-electron calculations using an original approach in the basis of numerical HF occupied orbitals and virtual Sturmian orbitals and also the calculations of 11-electron ECP based on Gaussian orbitals. The comparison of one-electron spectra of Ag2 energies in non-relativistic HF calculations using ECP with the all-electron numerical calculation shows that the difference between the corresponding orbitals does not exceed 2 × 10-3 au. For the Ag2 molecules, calculations are made, with both ECP and RECP, of the energy of two vertical dipole-allowed optical transitions. For the Ag+2 molecular ion, energies of five dipole-allowed optical transitions are predicted. The nature of low-lying electronic states of Ag2 is studied by analyzing Mulliken populations and the leading configurations that make the dominant contribution to the wave function of a many-electron state. The characteristics calculated in the paper are compared with experimental data and results of other theoretical papers.

AB - Ab initio calculations of spectroscopic constants and low-lying electronic states of Ag2 and Ag+2 dimers are reported. They are made by the Hartree-Fock (HF) method and the restricted active space self-consistent field (RASSCF) method with the aid of semilocal nonrelativistic and relativistic 11-electron effective core potentials (ECP and RECP). To find the quality of the potential constructed in this way, we made nonrelativistic calculations by the HF method of the Ag2 molecule, both all-electron calculations using an original approach in the basis of numerical HF occupied orbitals and virtual Sturmian orbitals and also the calculations of 11-electron ECP based on Gaussian orbitals. The comparison of one-electron spectra of Ag2 energies in non-relativistic HF calculations using ECP with the all-electron numerical calculation shows that the difference between the corresponding orbitals does not exceed 2 × 10-3 au. For the Ag2 molecules, calculations are made, with both ECP and RECP, of the energy of two vertical dipole-allowed optical transitions. For the Ag+2 molecular ion, energies of five dipole-allowed optical transitions are predicted. The nature of low-lying electronic states of Ag2 is studied by analyzing Mulliken populations and the leading configurations that make the dominant contribution to the wave function of a many-electron state. The characteristics calculated in the paper are compared with experimental data and results of other theoretical papers.

UR - http://www.scopus.com/inward/record.url?scp=0345473474&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0345473474

VL - 87

SP - 877

EP - 887

JO - OPTICS AND SPECTROSCOPY

JF - OPTICS AND SPECTROSCOPY

SN - 0030-400X

IS - 6

ER -