Transition properties of X2Σ+, A2Π, B2Σ+, C2Π, a4Σ+, and b4 Δ states of boron monosulfide

A number of experiments have been performed to measure the transition properties of the low-lying states of boron monosulfide; however, only a few theoretical results have been reported in the literature. Thus, the transition properties of several of the lowest-lying states are investigated herein. The potential energy curves of the Omega states generated from the X-2 Sigma(+), A(2)Pi, B-2 Sigma(+), C-2 Pi, a(4)Sigma(+), and b(4)Delta states and the transition dipole moments between them were calculated using icMRCI approach. The radiative lifetimes of the first 16 levels were of the order of 9 - 20, 12 - 22, and 1.3 - 6.5 mu s for the A(2)Pi(1/2) , A(2)Pi(3/2), and B-2 Sigma(+)(1/2) states, respectively; those were approximately 361 - 553 and 298 - 513 ns for the C-2 Pi(1/2) and C-2 Pi(3/2) states, respectively. The C-2 Pi(3/2) - X-2 Sigma(+)(1/2) , C-2 Pi(1/2) -X-2 Sigma(+)(1/2), and C-2 Pi(1/2) - A(2)Pi(3/2) transitions were the strongest, followed by the B-2 Sigma(+)(1/2) - A(2)Pi(3/2), B-2 Sigma(+)(1/2) - A(2)Pi(1/2) , and C-2 Pi(3/2) - A(2)Pi(1/2) transitions. The transitions from the a(4)Sigma+ and b(4)Delta states to the X-2 Sigma(+) state were evaluated. The radiative lifetimes of the first 16 levels were of the order of 3.2 - 6.0, 8.9 - 17.3, and 61 - 7644 ms for the a(4)Sigma(+)(3/2) , a(4)Sigma(+)(1/2), and b(4)Delta(5/2), respectively; those were approximately 15 - 1430 and 7 - 1006 mu s for theb(4)Delta(3/2) and b(4)Delta(1)(/2) states, respectively. Among these forbidden transitions, the emissions from the b(4)Delta(1/2) - X-2 Sigma(+)(1/2), b(4)Delta(1/2) - A(2)Pi(3/2), b(4)Delta(1/2) - A(2)Pi(1/2), b(4)Delta(1/2) - X-2 Sigma(+)(1/2) , b(4)Delta(1/2) - A(2)Pi(3/2), and b(4)Delta(1/2) - A(2)Pi(1/2) systems were strong. The distribution of the radiative lifetime at a level upsilon versus the rotational quantum number J was evaluated for the A(2)Pi(1)(/2) , A(2)Pi(3/2), B-2 Sigma(+)(1/2), C-2 Pi(1/2), and C-2 Pi(3/2) states. (C) 2021 Elsevier Ltd. All rights reserved.