Neji Khelifi

Ab initio adiabatic and diabatic energies and dipole moments of the KH molecule

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 bu...

Dynamic couplings, radiative and nonradiative lifetimes of the A1Σ+ and C1Σ+ states of the KH molecule

In this article, dynamic couplings for X-A, X-C, and A-C, by using first and second derivatives terms neglected in the Born–Oppenheimer approximation, are calculated. Newly calculated radiative transition probabilities for the A1Σ+→X1Σ+ and C1Σ+→X1Σ+ emission bands of KH are used to calculate the radiative and nonradiative lifetimes of the various vibrational levels (0⩽v⩽35) and (0⩽v⩽55) of A1Σ+ and C1Σ+ states of the diatomic potassium hydride, KH, molecule. For higher vibrational levels, an estimate of the bound-to-free emission probability is also needed and included. Accurate positions, radiative and nonradiative lifetimes of states belonging to the adiabatic A and C states of the KH molecule are estimated. The results come from a Fermi’s Golden Rule treatment in coupling calculation. That confirms the accuracy reached in both approaches and also in the treatment of the diabatic-adiabatic transformation. It involves, in particular, an effective phase choice that is needed to properly estimate nonadiab...