Ab-initio calculations of the electronic structure of the alkaline earth hydride anions XH- (X = Mg, Ca, Sr and Ba) toward laser cooling experiment

By the use of the ab initio CASSCF/(MRCI+Q) calculations in the representation (2s+1)Lambda((+/-)), the adiabatic potential energy curves and the dipole moment curves of the low lying states of the alkaline earth hydride anions (MgH-, CaH- SrH- and BaH-) have been investigated in their singlet and triplet multiplicities. The spectroscopic parameters T-e, R-e, omega(e), B-e, alpha(e), the dipole moment mu(e), and the dissociation energy D-e have been also calculated for the bound states of the considered molecules. In addition, a systematic investigation of the transition dipole moment curves for the lowest (1)Sigma(+)-(1)Pi transitions has been done along with the Franck-Condon factor (FCF) corresponding to the X-1 Sigma(+)-(1)(1)Pi transition. Using the canonical function approach, a rovibrational study has been performed for finding the rovibrational constants E-v, B-v, D-v and the turning points R-min and R-max for the ground and different excited bound state. Efficient routes may be achieved via the diagonal FCF for the formation of cold and ultracold alkaline earth hydride anions. (C) 2019 Elsevier B.V. All rights reserved.