Theoretical electronic structure with rovibrational calculations of the alkali chloride molecules XCl (X = Li, Na, K, Rb, Cs)

The adiabatic potential energy curves and the static dipole moment curves of the low-lying singlet and triplet electronic states in the representation ^2s+1Λ^(+/−) of the five alkali chloride molecules (LiCl, NaCl, KCl, RbCl and CsCl) have been investigated via ab initio calculations using the state averaged complete active space self consistent field followed by the Multi-reference single and double configuration interaction method with Davidson correction CASSCF/(MRCI + Q). For the molecules under consideration, the spectroscopic constants T _e, R _e, ω _e and B _e, the dipole moment μ _e, and the dissociation energy D _e have been calculated for the bound states along with the percentage ionic character f _ionic around the equilibrium position of the ground state. Moreover, the transition dipole moment curves of the X¹∑⁺–(2)¹∑⁺ and X¹∑⁺–(1)¹Π transitions have been investigated for the five alkali chloride molecules. A rovibrational calculation was carried out using the canonical functions approach in order to determine the rovibrational constants E _v, B _v and D _v and the abscissas of the turning points R _min and R _max for the investigated bound states. (paper)