Theoretical electronic structure of the cadmium monohalide molecules CdX (X = F, Cl, Br, I)

The potential energy and dipole moment curves for the lowest electronic states in the representation 2s+1Λ(±) of CdX (X = F, Cl, Br, I) molecules are investigated via complete active space self-consistent field (CASSCF) and multi-reference configuration interaction MRCI (single and double excitation with Davidson correction). For the bound states of CdX diatomic molecules the bond distances Re, the vibrational harmonic frequencies ωe, the rotational constants Be, the electronic energies relative to the ground state Te, and the permanent and transition dipole moments have been computed. The dissociation energy limits of the atomic levels of CdX compounds are also calculated. The transition dipole moment between the ground state X2Σ+ and (2)2Σ+ is investigated. Consequently, the transition dipole moment values of the upper state at its equilibrium position μ21, the emission angular frequency ω21, the Einstein coefficients of spontaneous and induced emissions (A21 and B21ω), the spontaneous radiative lifetime τspon, the emission cross section σ0, the line strength and the emission oscillator strength f21 are calculated along with the ionicity of the X2Σ+ and (2)2Σ+ states. The eigenvalues Ev, the rotational constants Bv, the centrifugal distortion constants Dv and the abscissas of the turning points Rmin and Rmax of X2Σ+ states of the CdX diatomics are computed. The comparison of the results with those available in literature shows a very good agreement.