Ab initio calculation on the potential energy curves and spectroscopic properties of the low-lying excited states of BCl

Abstract

The high level quantum chemistry ab initio multi-reference configuration interaction method with reasonably large aug-cc-pVQZ basis sets is used to calculate the potential energy curves of 14 -S states of BCl+ radical correlated to the dissociation limit B+(1Sg)+Cl(2Pu) and B(2Pu) +Cl+(3Pg). In order to get the better potential energy curves, the Davidson correction and scalar relativistic effect are taken into consideration. The spin-orbit interaction is first considered, which makes the lowest 4 -S states split to 7 states. The calculational results show that the avoided crossing rule exists between the states of the same symmetry. The analyses of the electronic structures of -S states determine the electronic transition of each state and demonstrates that the -S electronic states are multi-configurational in nature. Then the spectroscopic constants of the bound -S and states are obtained by solving the radial Schrdinger equation. By comparison with experimental results, the spectroscopic constants of ground states are in good agreement with the observed values. The remaining computational results are reported for the first time.