Accurate ab initio potential energy curves for the classic Li–F ionic-covalent interaction by extrapolation to the complete basis set limit and modeling of the radial nonadiabatic coupling

Abstract

Multireference configuration interaction calculations using large correlation consistent basis sets and full configuration interaction calculations with the smallest of such basis are utilized to describe the ionic-neutral curve crossing for the title system. The results of the former calculations have then been extrapolated to the complete basis set limit using the uniform singlet- and triplet-pair extrapolation scheme. A recent suggestion for locating the nonadiabatic matrix terms at the point where the dynamical correlation split vanishes has also been tested. Additionally, a consistent formalism is suggested to model the radial dependence of the nonadiabatic matrix terms that warrants an overlap dependence away from the crossing. When applied to LiF, the overall approach yields results in excellent agreement with the commonly accepted values for the geometric and energetic attributes at both the equilibrium and diabatic crossing regions.

Erratum: “Accurate ab initio potential energy curves for the classic Li–F ionic-covalent interaction by extrapolation to the complete basis set limit and modeling of the nonadiabatic coupling” [J. Chem. Phys. 131, 124128 (2009)]

“…A slight hump appears in V 12 at the location of maximum adiabatic interaction but much less peaked than before. 1 An enhanced similarity with other curves 2-5 is apparent. Upon diagonalization, the adiabats are exactly reproduced.…”

“…(26) of Ref. 1. Although fits to the calculated NACTs using both a Lorentzian form (L1) and sums of up to three logistic functions (for the cumulative probability) or bell-shaped curves (for the transition probability) have been reported, 1 only the latter (denoted S3, with components S3-A, S3-B, and S3-C) will be considered here.…”

Ab initiopotentials ofF+Li2accessible at ultracold temperatures

“…The work by Varandas [24] on LiF has shown that this quality of basis set can achieve an accuracy within 1% of the complete basis set (CBS) limit. The simplest calculations performed used DFT and a variety of exchange functionals in an attempt to model the entrance and exit channels of the ground potential energy surface and to determine the minimum energy geometry of the M 2 + X reactions Li 2 + [F, Cl, Br] and F + [Na 2 , K 2 ].…”

Unified treatment of field-induced and intrinsic nonadiabatic transitions with a generalized Floquet Hamiltonian method

“…Theoretical studies on LiF in recent years include static ab initio calculation of PESs [45,46], and calculations of field-induced dynamics [47,48]. To the best of our knowledge, no experimental study on its field-induced dynamics has ever been reported, but it still serves as a prototype for studying an interplay of field-induced and intrinsic nonadiabatic transitions.…”