Accurate spectroscopic calculations of the 21 Λ-S states and 42 Ω states of the SiB radical

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The potential energy curves were calculated for the 21 Λ-S states, which were generated from the first two dissociation channels, Si(3Pg)+B(2Pu) and Si(1Dg)+B(2Pu), of the SiB radical. The potential energy curves were computed for the 42 Ω states, which arose from the 21 Λ-S states. The calculations were done using the CASSCF method, which was followed by the icMRCI approach. Of these 21 Λ-S states, the D4Σ−, i2Σ+, j2Π, 52Π, and 12Φ states had double wells. The D4Σ−, a2Π, A4Π, e2Π, j2Π, 52Π, h2Δ, and 12Φ states were inverted with the spin-orbit coupling effect taken into account. The 32Δ state and the second wells of D4Σ− and 12Φ states were weakly bound. Core-valence correlation correction, scalar relativistic correction and Davidson correction were included. The spectroscopic parameters were determined and the vibrational properties of some weakly-bound states were predicted. The spin-orbit coupling effect on the spectroscopic parameters was evaluated. Comparison with available experimental data shows that the methodology used is highly accurate for the SiB radical.