Radiative lifetimes of A 2Π, B 2Σ+, a 4Σ+, and b 4Δ states of CP radical

Abstract The potential energy curves of X 2Σ+, A 2Π, B 2Σ+, a 4Σ+, and b 4Δ states and their Ω states of CP were calculated using the icMRCI approach. The transition dipole moments between these states were computed. To improve the accuracy of the potential energy curves, core–valence correlation and scalar relativistic corrections were considered. The radiative lifetimes were approximately 10 μs for the A 2Π3/2 and A 2Π1/2 states and 100 ns for the B2Σ+1/2 state; those were approximately 10, 10 – 100, 10, 0.1 – 1, and 10 ms for the a 4Σ+1/2, a 4Σ+3/2, b 4Δ1/2, b 4Δ3/2, and b 4Δ5/2 states, respectively. The spontaneous emissions from the B 2Σ+1/2 – X 2Σ+1/2 system were strong, followed by the A 2Π3/2 – X 2Σ+1/2, A 2Π1/2 – X 2Σ+1/2, B 2Σ+1/2 – A 2Π3/2, and B 2Σ+1/2 – A 2Π1/2 transitions. The strong emissions from the A 2Π3/2 – X 2Σ+1/2 and A 2Π1/2 – X 2Σ+1/2 systems were in the infrared region; those from the B 2Σ+1/2 – X 2Σ+1/2 system were in the visible and ultraviolet regions; and those from the B 2Σ+1/2 – A 2Π3/2, and B 2Σ+1/2 – A 2Π1/2 systems were of visible light. A simple comparison shows that the effect of the spin–orbit coupling on the radiative lifetimes of the A 2Π and B 2Σ+ states was significant. The radiative–lifetime distribution of each level υ versus the rotational quantum number J was evaluated for υ ≤ 15 and J ≤ 70.5.