Theoretical investigation of the van der Waals interaction in Ba^0,+,2+He systems and the stability of Ba²⁺He _n clusters

Abstract

An ab-initio calculation was performed to highlight the van der Waals interaction between Ba0,+,2+ and helium atoms. The low-lying electronic states for Ba+He and BaHe systems have been determined with the ECP-CPP and full valence CI theory. However, the core-core interaction for Ba++He has been calculated by the CCSD(T). As a result, the spectroscopic parameters and the vibrational levels have been derived from Potential Energy Surface (PES) and compared with available theoretical and experimental data. Then, the permanent dipole moments for the ground and the excited states are determined. These results show an important shape in PES and allow checking the strong repulsive interactions between Rydberg electrons and the He atom. Furthermore, structures and stabilities of the Ba++Hen mixed-clusters have been investigated by exploring the PES based on the BHMC algorithm. The most stable icosahedral structure was detected at n = 12 and the snowball shell was completed at n = 20.

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr2, Fr–AEM+ (AEM= Ca, Sr, Ba)]

“…After contraction, this number of functions is reduced to 42, 48, 54, and 51; the basis sets become (8s/4p/5d), (8s/5p/5d), (8s/7p/5d), and (8s/6p/5d). These basis sets have given reliable results in other published works. ,,− …”

“…In order to obtain accurate structural and spectroscopic properties within the Born-Oppenheimer approximation, we have adopted the computational scheme successfully applied to the ground and excited states interactions between heteronuclear alkali metal dimers and mixed alkali–AEM ions. − Hence, we have realized a non-relativistic electronic-structure computation of the neutral and cationic systems involving the radioactive atom Fr [Fr 2 , Fr–AEM + (AEM = Ca, Sr, Ba)]. The investigated dissociation limits of Fr 2 homonuclear dimer are {Fr­(7s) + Fr­(7s, 7p, 6d, 8s, 8p)}.…”

Computational study of the electronic structure of the Srm+Kr (m = 0, 1) van der Waals complexes

“…In the theoretical scheme, various authors studied the spectroscopic characteristics of the diatomic molecules formed by the metal species [29][30][31][32][33][34][35][36][37][38][39][40]. Tomza and co-workers [38] studied the excited electronic states of the Sr 2…”