Theoretical Study on the Electronic Structure and Transition Properties of Low Excited States of SeCl⁺

Abstract

For the first time, the spectroscopy and transition properties of SeCl + are systematically reported. The potential energy curves of 22 Λ − S states and the corresponding 51 Ω states in the first and second dissociation channels of SeCl + are calculated using the internally contracted multiconfiguration interaction and Davidson correction method. The phenomenon of avoided crossing in Ω states below 30,000 cm −1 is discussed in detail. The spectroscopy constants are obtained by fitting the potential energy curves, and also the Franck− Condon factors and radiation lifetimes of the X 3 Σ 0 + − ↔ 2 1 Σ 0 + + transition are calculated. Between X 3 Σ 0 + − and 2 1 Σ 0 + + , the Franck−Condon factors are large, close to 1, but the radiation lifetime is large too. According to the calculation results, it is determined that direct laser cooling of SeCl + is considered infeasible.

Theoretical calculation of spectroscopy properties of selenium bromide cation

“…Based on the obtained potential energy curves, we obtained the spectroscopic data of some of the lower excited states by solving the one-dimensional radial Schrödinger equation and show them in Table 6 . The vertical transition energy from the first excited state( X 3 Σ − 1 (1)1) to the ground state is 418 cm −1 , compared with 13 cm −1 , 191 cm −1 , and 965 cm −1 for SF + , 37 SeCl + , 23 and TeCl + 24 of the same main group, respectively. It can be noticed that this value becomes larger and larger as the relative atomic mass increases.…”

“…, compared with 13 cm −1 , 191 cm −1 , and 965 cm −1 for SF + , 37 SeCl + , 23 and TeCl +24 of the same main group, respectively. It can be noticed that this value becomes larger and larger as the relative atomic mass increases.…”

“…Table 3 shows the spectrum constants of the low excited electronic states of ions in the same main group as SeBr + . The equilibrium bond lengths of SCl + , 22 SeCl + , 23 TeCl +24 show an increasing trend, while the rest of the spectrum constants show a decreasing trend. The equilibrium bond lengths of the low excited electronic states of SeBr + are larger than those of SeCl + and smaller than those of TeCl + .…”

“…For SCl + of the same main group, Lu et al 22 calculated the spectroscopic data of the ground and low excited states of this ion, detailed potential energy curves in the Ω state and the potential laser-cooled transition in the Ω state. Wang et al 23,24 calculated the spectroscopic data of SeCl + and TeCl + in the Λ–S state as well as in the Ω state, compared in detail the spectroscopic properties in the presence of the same main group of ions, and concluded from detailed calculations that direct laser cooling of SeCl + and TeCl + is not feasible. Meanwhile, molecules with the same electronic state structure and the same potential energy curve trend as SeBr + have also been extensively studied, and Belinassi 25 investigated the transition properties between the ground state to the lower excited state of the SeI molecule.…”

Ab Initio Calculation of Ground- and Low-Excited-State Spectroscopic Data and Transition Properties of SBr+

“…However, the Frank–Condon factor and radiation lifetime from the ground state to the low excited state are not given in the literature of SCl + , so they did not analyze whether there is a transition suitable for laser cooling. Meanwhile, Wang et al , calculated the spectrum data of SeCl + and TeCl + , calculated the spectrum of the lower excited states of these two molecules in detail, compared the differences existing between the two and the same main-group molecules, and discussed in detail the existence of the avoided crossing in the Ω state. Based on the spectrum data and the transition data calculated by Wang et al, they finally concluded that SeCl + and TeCl + are not suitable for laser cooling.…”