Electronic Structure with Rovibrational Calculations of the Magnesium Monohalides MgX and Their Cations MgX⁺ (X = Cl, Br, and I)

Alkaline-earth monohalides are popular compounds that are used in various applications. Little is known, however, in terms of electronic structure, about their cations and their low-lying electronic states. We present in this work electronic structure ab-initio calculations based on multireference configuration interaction plus Davidson correction of three magnesium monohalides and their cations (MgCl, MgBr, MgI, MgCl⁺, MgBr⁺, and MgI⁺). We determine the spectroscopic constants T_e, R_e, ω_e, B_e, and α_e and the dissociation energies D_e for their bound states. Additionally, we investigate their vibrational properties by calculating the vibrational eigenvalue E_v, the rotational constant B_v, and the centrifugal distortion constant D_v. We additionally study the electric charge distribution of several states by determining their permanent dipole moment and transition dipole moment curves. Finally, we calculate the Franck-Condon factors and the radiative lifetimes as precursors for laser cooling experiments.