Ab Initio Adiabatic and Diabatic Energies and Dipole Moments of the CaH⁺ Molecular Ion

Abstract

The diabatic and adiabatic potential-energy curves and permanent and transition dipole moments of the highly excited states of the CaH(+) molecular ion have been computed as a function of the internuclear distance R for a large and dense grid varying from 2.5 to 240 au. The adiabatic results are determined by an ab initio approach involving a nonempirical pseudopotential for the Ca core, operatorial core-valence correlation, and full valence configuration interaction. The molecule is thus treated as a two-electron system. The diabatic potential energy curves have been calculated using an effective metric combined to the effective Hamiltonian theory. The diabatic potential-energy curves and their permanent dipole moments for the (1)∑(+) symmetry are examined and corroborate the high imprint of the ionic state in the adiabatic representation. Taking the benefit of the diabatization approach, correction of hydrogen electron affinity was taken into account leading to improved results for the adiabatic potentials but also the permanent and transition electric dipole moments.

Ab initio calculation of the electronic structure of the strontium hydride ion (SrH+)

“…The computed PDM value of the ground state for these cations provides estimation for the associated Stark shifts . In addition the good quality calculations of electric dipole properties (PDM) on molecules such as CaH + , BaH + , and MgH + are very interesting and constitute the first step to illustrate the repartition of charges in the adiabatic states . Consequently, we have investigated the PDM and TDM functions of SrH + for all states bellow the ionic limit mainly to better know the ionic character of the 1 Σ + states at the vicinity of the avoided crossing and in the other symmetries also.…”

“…We note also that the crossings seen in the dipole moment curves coincide with the crossings positions previously seen in the PECs. The PDM can, thus, give interesting information about the physical nature of the states as for the molecules CaH + , BaH + , and MgH + . Let us recall that the avoided crossing may have significant role for the excitation or charge transfer efficiency.…”

“…Motivated by the numerous experimental works on alkaline earth hydrides cation, numerous theoretical investigations have been performed for YH + systems . Both adiabatic potential energy and dipole moments of these diatomic hydride cations have been investigated by various numerical methods.…”

Depolarizing Collisions With Hydrogen: Neutral and Singly Ionized Alkaline Earths

“…Such a diabatization procedure has already been done for some of the states of MgH (Belayev et al 2012) and CaH + (Habli et al 2011). Some work in this direction is now being done in order to assess the necessity of a more exact treatment for the collisional depolarization of atoms in excited electronic states, including inelastic transitions between different L, S A manifolds.…”

Charge transfer ionic character illustration for strontium hydride ion through a diabatic investigation

“…In the last years, studies on structure and electronic properties of the alkaline earth hydrides ions have developed rapidly on both experimental and theoretical side . The evaluation of the charge localization character of these systems is of great interest, both from the experimental and theoretical point of view.…”