Spin–orbit configuration-interaction study of valence and Rydberg states of LiBe

Abstract

A b initio spin–orbit full configuration-interaction calculations in the context of relativistic effective core potentials are reported for the weakly bound metal dimer LiBe, a three-valence-electron system. The effects of basis set on the energies of valence and Rydberg states of the cluster are discussed, as are the effects of configuration space selection on the energy of the latter states. Results at the dissociative limit are compared to the experimental atomic spectra. Potential-energy curves and spectroscopic constants are presented for the ground state and fourteen excited states, which includes the Li and Be 2p valence states, the Li 3s, 3p, 3d, and 4s Rydberg states, as well as three low-lying states of the molecular cation.

Ground- and excited-state properties of the polar and paramagnetic RbSr molecule: A comparative study

“…The electronic structure of Ba neutral compounds (BaLi, BaNa, BaK) has been explored some time ago by Allouche and coworkers [38][39][40]. Other studies concern CaLi [41][42][43], LiBe [44,45]. More recently the electronic structure of the related molecular ions containing one alkali atom and Ca + [46], Sr + [47] or Ba + [48][49][50][51] with various high-level approaches have been published in relation with experiments aiming at creating cold molecular ions in merged cold ion and cold atom traps.…”

Long-range coefficients for the low-lying electronic states of BeLi and Be2

“…Concerning this kind of molecule for which several theoretical studies have been reported, with results and predictions often quite contradictory, experimen-talists and theoreticians have recently focused specific attention on the study of their low-lying electronic states. 11,[14][15][16] With regard to the dissociative channels, these studies demonstrate that there is a need for high level ab initio investigations on the asymptotic long-range properties.…”

“…6,7 Nowadays, many ab initio calculations yield a slightly attractive ground state for LiBe and the beryllium dimer Be 2 . [8][9][10][11][12][13] Difficulties and differencies between the calculation are usually assigned to the quasidegeneracy of the 2s and 2p orbit- als of the Be atom. Highly sophisticated ab initio methods with very high angular moment basis functions are needed for the accurate calculation of the electronic structure and properties of these compounds.…”

“…If reliable values are available for atom-atom systems in which the atoms are in their ground state, very little is precisely known for excited atoms. There is a great current interest in the structure and chemical properties of small metal clusters, [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] notably those containing Group II elements characterized by weakly bound states and excited states. Experimental techniques combining YAG laser vaporization with collisional cooling are well suited to study weakly bound molecules of this kind.…”

“…Be 2 ͑Refs. 14-16, 21-32͒ and LiBe [6][7][8][9][10][11] are, respectively, the simplest and lightest homonuclear and heteronuclear metal clusters. Concerning this kind of molecule for which several theoretical studies have been reported, with results and predictions often quite contradictory, experimen-talists and theoreticians have recently focused specific attention on the study of their low-lying electronic states.…”