Multireference relativistic configuration-interaction calculations for (d+s)ntransition-metal atomic states: Application to Zr ii hyperfine structure

Abstract

Our relativistic configuration-interaction (RCI) methodology has been extended to multireference cases, and improved to permit the construction of angular-momentum functions of arbitrary size, and to minimize the number of vectors needed with each configuration. We report RCI calculations on the fine (fs) and hyperfine (hfs) structure for the (d+s) J=0.5 and 1.5 levels of ZrII. The average fs error is 0.075 eV, and 17% for hfs, when compared to available experiment. These results indicate that it is possible to correctly position all levels of (d +s)" configurations in the transition-metal atoms.PACS number(s): 31.30. Gs, 31.20.Tz, 31.30.Jv

Theoretical lifetimes of Nb iiz4d35G3oBeck1, Datta2 1995Phys. Rev. ASelf Cite9140View full textAdd to dashboardCite

“…There are also important "Pauli exclusion" effects present, associated with the core pair excitations 4p -+4d +4d Ud, which can differ as much as a few tenths of an eV from level to level. These must be included, if accurate results for all the (d +s)" levels are to be obtained, as is being recognized [2,14].…”

“…For many states d" and d'" "s eigenfunctions interact strongly, due to near degeneracy effects. This was found to have important consequences for hfs [1,2], and here we investigate just what the impact on the f values might be. There are three reasons for choosing to investigate Nb?I lifetimes:…”

Hyperfine-structure studies of Nb ii: Experimental and relativistic configuration-interaction results

“…As in our earlier studies of twoand threevalence-electron systems, namely Sett [1], YII [2], Tilt [3], and Zr tt [4], the experimental studies on these singly charged ions are conducted using the laser-rf doubleresonance method and compared with theoretical results obtained using a relativistic configuration-interaction (CI) algorithm [5]. This study is motivated by the success of the many-body theoretical treatment for hyperfine structure at the sub-10% level in the two- [6] and three- [4,7] valence-electron cases and the desire to explore the more complex four-electron situation. An alternative ab initio approach to hfs is that of Hartley and Martensson-Pendrill [8], who have applied a combination of a discrete numerical basis and random-phase approximation diagrams to determine the hyperfine structure of Cs and Tl.…”

“…This problem has been recognized as a formidable task for some time [9 -12]. Despite the complexity of these transition-metal systems and the difhculty in even obtaining the correct ordering of fine-structure levels, there has been renewed interest in the ab initio calculation of hfs as a test of the accuracy of the wave function near the nucleus [7,13,14]. The form of the wave function is dictated by first-order perturbation theory and its parameters (Z', CI coefficients) are 'Present address: Department of Quantum Engineering and System Science, University of Tokyo, Tokyo 113,Japan.…”

“…The form of the wave function is dictated by first-order perturbation theory and its parameters (Z', CI coefficients) are 'Present address: Department of Quantum Engineering and System Science, University of Tokyo, Tokyo 113,Japan. determined by the energy variational principle [5,7,15]. Once a reasonably accurate description of the energy is obtained, the configuration-state functions important for hyperfine structure are included.…”