The Li···HF van der Waals minimum and the barrier to the deep HF–Li potential well

Abstract

Molecular beam experiments (lithium atom plus hydrogen fluoride) by both Becker and co-workers (C.H. Becker, P. Casavecchia, P.W. Tiedemann, J.J.Valentini, and Y.T. Lee, J. Chem. Phys. 73, 2833 (1980)) and Loesch and Stienkemeier (H.J. Loesch and F. Stienkemeier, J. Chem. Phys. 98, 9570 (1993)) deduced a van der Waals complex of type Li···HF. In this research, molecular electronic structure theory [aug-cc-pCVQZ CCSD(T)] has been used to predict a well depth of 0.86 kcal mol−1 relative to separated Li + HF. However, the barrier from this vdW well to the more strongly bound (∼6.2 kcal mol−1) HFLi complex lies 0.43 kcal mol−1 below separated Li + HF.