Radiative lifetimes of the 11Σ–, 11Δ, 21Σ+, a3Π, 13Σ+, d3Δ, and e3Σ– states of carbon monosulfide

Abstract

Numerous experimental and theoretical investigations studied the transition properties of the A1Π – X1Σ+ system of carbon monosulfide. However, only a few transition properties are currently available except for the A1Π state. Therefore, this study calculated the properties of the dipole-allowed transitions arising from the 11Σ–, 11Δ, 21Σ+, a3Π, 13Σ+, d3Δ, and e3Σ– states and the spin–forbidden transition from the a3Π to the X1Σ+ state. The radiative lifetimes were approximately 10 ns for the 21Σ+ state, 10 μs for the e3Σ– state, 10 – 100 μs for the d3Δ state, and 10 – 1000 μs for the 13Σ+ state. The emissions from the 21Σ+ – X1Σ+ system were strong. The radiative lifetimes were of the order of 0.1 – 1000 ms for the 11Δ state and 0.1 – 105 ms for the 11Σ– state. The lower the vibrational level of the 11Δ and 11Σ– states was, the longer the radiative lifetime became, suggesting that the spontaneous emissions arising from the lower vibrational levels of the two states were difficult to be measured through spectroscopy. The radiative lifetimes were of the order of 1 – 10 and 1 ms for the a3Π1 and a3Π0+ states, respectively; whereas those of the a3Π2 and a3Π0– states were extremely long. The radiative–lifetime distribution varying with the rotational angular quantum number J was investigated at J ≤ 70 for a particular vibrational level of the 11Σ–, 11Δ, 21Σ+, a3Π, 13Σ+, d3Δ, e3Σ–, a3Π1, and a3Π0+ states.