The calculation of f-f spectra of lanthanide and actinide ions by the MCDF-CI method

Abstract

The calculation of f-f spectra of lanthanide and actinide ions by the multiconfiguration Dirac-Fock configuration interaction (MCDF-CI) method is discussed. The U 4+ , Pr 3+ , Np 3+ , Pm 3+ , Am 3+ and Eu 3+ ions are considered in detail. The effects of the different classes of excitation included and the flexibility of the basis of one-particle functions used on the calculated spectra are discussed. Breit and size-extensivity corrections are also considered. Reasonably accurate (errors <500 cm −1 ) spectra of U 4+ and Pr 3+ are achieved fairly readily and the best spectra of these ions are comparable with the most accurate published calculations. The best spectra of the other ions are less accurate but are in significantly better agreement with experiment than any previous ab initio calculation.

Core correlating basis functions for elements 31–118

“…The core correlating functions were optimized in DiracCoulomb singles and doubles CI (SDCI) calculations on the shell of highest angular momentum for each principal quantum number, using RAMCI [37]. All singles and doubles from the specified shell into the correlating space that couple with that shell to J = 0 were taken.…”

Relativistic double-zeta, triple-zeta, and quadruple-zeta basis sets for the 7p elements, with atomic and molecular applications

“…All atomic calculations were carried out with GRASP [54,57] and RAMCI [55], using the Dirac-Coulomb Hamiltonian and the standard Gaussian nucleus [56]. The coefficient of fractional parentage (CFP) package in RAMCI was supplemented for j = 9/2,11/2 and 13/2 to allow the use of higher than double excitations with high angular momentum functions.…”

“…The methods used have been described previously [40,42,54,55]. The SCF basis sets were optimized in Dirac-Hartree-Fock calculations using the Dirac-Coulomb Hamiltonian with the standard Gaussian nuclear charge distribution [56].…”

Energies and Electric Dipole Transitions for Low-Lying Levels of Protactinium IV and Uranium V

“…Morton extended his previous work [27] for resonance absorption lines adding technetium, thorium, and uranium [28]. Seth et al [29] calculated f-f spectra of lanthanide and actinide ions by the multiconfiguration Dirac-Fock configuration interaction (MCDF-CI) method considering uranium V, praseodymium IV, neptunium IV, promethium IV, americium IV, and europium IV ions.…”