The low-lying states of AlC and GaC: Molecular constants, transition probabilities and radiative lifetime

Highlights: • Low-lying electronic states of the AlC and GaC molecules. • Transition probabilities and radiative lifetime. • Molecular constants. The electronic states correlated to the first dissociation channel, around 25,500 cm⁻¹, of the AlC and GaC molecules have been investigated by CASSCF/MRCI methodology with aug-cc-pV5Z basis set. Our work focused on the accurate description of the potential energy curves, dissociation energies, transition moment functions, radiative lifetimes, dipole moments and molecular constants. The B⁴Σ⁻ electronic state has been previously detected for AlC molecule and it is probably not detectable in GaC molecule due to the predissociative character which affects all its vibrational levels. The characterization of the GaC low-lying electronic states were carried out for the first time.