Transition dipole moments and probabilities of the CCl radicals

Abstract

This work studies the transition dipole moments and properties of 12 electronic states. These states are X2Π, A2Δ, B2Σ+, C2Π, 12Σ−, 22Σ−, a4Σ−, b4Π, 14Σ+, 14Δ, 24Π, and 24Σ−; they originate from the first dissociation limit of the carbon monochloride radical. The potential energy curves were calculated using the complete active space self-consistent field method, followed by the valence internally contracted multireference configuration interaction approach. The B2Σ+ state has a double well and C2Π a single barrier. The radiative lifetimes of the vibrational levels are in the order of 10−7 s for the A2Δ state, and 10−7 and 10−5 s for the first and second wells of the B2Σ+ state, respectively, suggesting that the spontaneous emissions originated from the two states can easily occur. The radiative lifetimes are long for C2Π, b4Π, 14Δ, 14Σ+, and 24Π states and the Einstein A coefficients are small for the emissions originated from these states, indicating that the spontaneous emissions generated from these states are difficult to measure through spectroscopy. The 12Σ−, 22Σ−, and 24Σ− states are repulsive. Furthermore, the spectroscopic parameters and vibrational levels were evaluated. For the A2Δ – X2Π and B2Σ+ – X2Π systems, the Einstein A coefficients of the vibronic emissions are large, indicating that the emissions from the two systems can be easily detected by spectroscopy. The spectral range of the spontaneous emissions was evaluated for certain transitions.