Electronic structure of the ZnCl molecule with rovibrational and ionicity studies of the ZnX (X = F, Cl, Br, I) compounds

Based on the complete active space self consistent field (CASSCF) method with multi-reference configuration interaction MRCI calculations including single and double excitations with Davidson correction (+Q), twenty three low lying electronic states in the (2s+1)A((+/-)) representation of the zinc monochloride ZnCl molecule are investigated considering 7 and 9 valence electrons. The internuclear distance Re, the harmonic frequency omega(e), the permanent dipole moment mu, the rotational constant B-e and the electronic transition energy with respect to the ground state T-e are calculated for the bound states. The transition dipole moment between some doublet states is used to determine the Einstein spontaneous A(21) and induced emission B-21(omega) coefficients, the spontaneous radiative lifetime tau(spon), the emission wavelength lambda(21), the oscillator strength f(21) and the line strength S-21. The fraction of the ground state ionic character f and equilibrium dissociation energy D-E,D-e are also computed. Using the canonical function approach, the eigenvalues E-v, the rotational constants B-v, the centrifugal distortion constants D-v and the abscissas of the turning points R-min and R-max of the zinc monohalide molecules ZnX (X: F, CI, Br, I) are calculated. The comparison between the values of the present work and those available in the literature for several electronic states shows good accordance. (C) 2016 Elsevier B.V. All rights reserved.