Accurate calculations of spectroscopic parameters, transition properties of 17 Λ-S states and 32 Ω states of SiB⁺ cation

Abstract

This work computed the potential energy curves of 17 Λ-S states, which came from the first three dissociation limits, Si⁺(²P_u) + B(²P_u), Si(³P_g) + B ⁺(¹S_g), and Si(¹D_g) + B⁺(¹S_g), of the SiB⁺ cation. The potential energy curves were also calculated for the 32 Ω states generated from these Λ-S states. The calculations were done using the CASSCF method, which was followed by internally contracted MRCI approach with Davidson correction. To obtain the reliable and accurate spectroscopic parameters and vibrational properties, core-valence correlation and scalar relativistic corrections were included. Of these 17 Λ-S states, the C³ Σ ⁺, E³Π, 3³Π, 2³Σ⁺, 2¹Π, and 3¹Σ⁺ states had double wells. The 3¹Π state had three wells. The D³Σ⁻, E³Π, 3³Π, and B³Δ states were inverted with the spin-orbit coupling effect accounted for. The 2¹Δ state, the first well of 3¹Σ⁺ state, the second wells of 3³Π, 2³Σ⁺, and 2¹Π states and the second and third wells of 3¹Π state were weakly bound, which well depths were within several hundreds cm^-1. The second well of 3¹Π state had no vibrational states. The first wells of E³Π and 3¹Σ⁺ states had only one vibrational state. The spectroscopic parameters were evaluated. The vibrational properties of some weaklybound states were predicted. Franck-Condon factors of some transitions between different two Λ-S states were determined. The spin-orbit coupling effect on the spectroscopic parameters and vibrational properties was discussed. These results reported here can be expected to be reliably predicted ones.

Graphical abstract