Electronic states, spectroscopic properties, electronic transitions, and bonding in ScH2+: A thermodynamic stable transition metal-hydrogen dication

Abstract

Eight bound singlet and triplet electronic states of the diatomic dication ScH2+ are characterized theoretically at the SA-CASSCF/icMRCI/aug-cc-pV5Z level of theory by the construction of potential energy curves, and the evaluation of spectroscopic parameters. The states dissociating into the first channel are all thermodynamically stable. For the ground state, covalent bonding plays a relevant role in the stabilization of the molecule; for the other states, bonding results mainly from electrostatic charge-induced dipole interaction. Dipole moment (relative to the center of mass) functions and vibrationally averaged dipole moments quantify the polarity of the molecule. After evaluating transition moment functions, transition probabilities for spontaneous emission for selected pair of states are estimated by the Einstein Av´,v´´ coefficients and the stronger transitions identified; radiative lifetimes are also reported. Not yet known experimentally, this work is expected to motivate experimental investigations of transition metal-monohydrides diatomic dications.