Theoretical study of the electronic structure of the alkaline earth BeLi²⁺ ion

Issue title: Atomic and molecular nonlinear optics: Theory, Experiment and Computation A homage to the pioneering work of Stanisław Kielich (1925-1993)

Guest editors: G. Maroulis, T. Bancewicz, B. Champagne and A.D. Buckingham

Article type: Research Article

Authors: Farjallah, M.^a | Ghanmi, C.^a | Berriche, H.^{a; b; *}

Affiliations: [a] Laboratoire de Physique et Chimie d'Interfaces, Département de Physique, Faculté des Sciences de Monastir, Avenue de l'Environnement, 5019 Monastir, Tunisia | [b] Physics Department, College of Science, King Khalid University, P. O. Box 9004, Abha, Saudi Arabia

Correspondence: [*] Corresponding author. E-mails: hamid.berriche@fsm.rnu.tn, hamidberriche@yahoo.fr

Abstract: In this work, we present the structural and the spectroscopic properties of the alkaline earth BeLi2+ ion for all the electronic states dissociating into Be+(2s, 2p, 3s, 3p, 3d, 4s, 4p, and 4d) + Li+ and Be2+ + Li (2s and 2p). We have used an ab initio approach involving a non-empirical pseudopoential for the Li+ and Be2+ cores and core-core and core-valence correlation corrections. For our best knoweledge, the adiabatic potential energy curves and the spectroscopic constants for nearly 18 electronic states of 2Σ +, 2Π and 2 Δ symmetries are determined here for the first time. As neither experimental nor theoretical data are available for BeLi2+, our results are discussed and compared with similar systems such as BeH2+. Numerous avoided crossings between the electronic states of 2Σ+ and 2Π symmetries have been localised and analysed. Their existences are related to the interaction between the potential energy curves and the charge transfer process between the two ionic systems Be(2+)Li and Be+Li+. Furthermore, we have calculated the adiabatic transition dipole moments from X2Σ+, 22Σ+ and 32Σ+ states to the higher electronic states of the same symmetry. This study represents the necessary initial step towards the investigation of the charge transfer processes in collision between Be+-Li+ and Be2+-Li.

Keywords: Ab initio, pseudopotentials, potential energy curves, spectroscopic constants, avoided crossing, transition dipole moments

DOI: 10.3233/JCM-2010-0315

Journal: Journal of Computational Methods in Sciences and Engineering, vol. 10, no. 3-6, pp. 139-147, 2010