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

The potential energy curves were calculated for the 21 Lambda-S states, which were generated from the first two dissociation channels, Si(P-3(g)) + B(P-2(u)) and Si(D-1(g)) + B(P-2(u)), of the SiB radical. The potential energy curves were computed for the 42 Omega states, which arose from the 21 Lambda-S states. The calculations were done using the CASSCF method, which was followed by the icMRCI approach. Of these 21 Lambda-S states, the D-4 Sigma(-), i(2)Sigma(+), j(2)Pi, 5(2)Pi, and 1(2)Phi states had double wells. The D-4 Sigma(-), a(2)Pi, A(4)Pi, e(2)Pi, j(2)Pi, 5(2)Pi, h(2)Delta and 1(2)Phi states were inverted with the spin-orbit coupling effect taken into account. The 3(2)Delta state and the second wells of D-4 Sigma(-) and 1(2)Phi 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. (C) 2016 Elsevier B.V. All rights reserved.