Theoretical Investigation Of The Alkali-dimer Cation K_2~+: Potential Energy, Dipole Moment And Atomic Polarizabilities

摘要

The potential energy curves of the electronic states of ~2∑_(g,u)~+, ~2Π_(g,u) and ~2Δ_(g,u) symmetries of the K_2~+ molecular ionic system dissociating into K (4s, 4p, 5s, 3d, 5p, 4d and 6s) + K~+, have been calculated. The computation was performed using an ab initio approach, where a non-empirical pseudopotential for the K~+ core has been involved and a core-core and core valence correlation corrections have been added. The spectroscopic constants have been derived and compared with the available theoretical and experimental works. A good agreement has been obtained for the ground and the first excited states. However, a clear disagreement between this study and the model potential work of Magnier and Aubert-Fiecon [J. Quant. Spect. Rad. Trans. 78, 2003] has been observed for several excited states. They found that the 5~2∑_u~+, 6~2∑_g~+, 6~2∑_u~+, 7~2∑_g~+, 7~2∑_u~+, 4~2Π_g and 2~2 Δ_u states are repulsive, although they are attractive with potential well depths of 10, 100 and 1000 cm~(-1) in our study. Furthermore, the atomic polarizabilities have been predicted from a vibrational spacing analysis based on the WKB approximation applied on the potential energy at long-range distances. These polarizabilities have been used to reproduce the long range potential interaction for some electronic states.