Rovibrational properties of the A1Π – X1Σ+ system of the AlCl radical

Abstract

The potential energy curves of the X1Σ+ and A1Π states of aluminum monochloride radical and the transition dipole moments between them were calculated using the icMRCI approach. Core–valence correlation and scalar relativistic corrections were applied. The extrapolation of the potential energies to the complete basis set limit was considered to improve the quality of the potential energy curves. In order to accurately calculate the rovibrational transition positions of the A1Π – X1Σ+ system, the experimental Te value of the A1Π state was used to improve the reliability of the ab initio results. The radiative lifetimes of all vibrational states of the A1Π state were calculated and compared with the available experimental and theoretical results. The variation of the radiative–lifetime distribution with the rotational quantum number was obtained. The rovibrational transition positions, Einstein A coefficients, oscillator strengths, and Franck–Condon factors of the P, Q, and R branches of the vibronic emissions of this system were calculated up to J = 150. The Einstein A coefficients were large for numerous vibronic bands, indicating that these transitions were easily measured via spectroscopy. A Comparison with available measurements shows that the transition properties reported herein are accurate.