Simplest halogen atom plus alkali dimer potential surface: F+Li2→LiF+Li

Ab initio electronic structure calculations have been carried out to investigate some features of the potential energy surface for the chemical reaction F+Li2→LiF+Li. The basis set of contracted Gaussian functions was of ``double zeta plus polarization'' quality, with an additional set of p functions on F added to describe F−. Single-configuration and two-configuration self-consistent-field calculations are reported here. A minimum energy path was obtained for the collinear reaction, but the most important feature determined was the nature of the potential minimum due to the FLi2 complex. For linear F–Li–Li, this complex is bound by 4 kcal/mole relative to separated LiF + Li. The attraction is much stronger, 34 kcal, for C2v geometry, and this species is predicted to have a bond angle of 99° and Li–F bond distance of 1.79 Å. Several excited electronic states of FLi2 are discussed briefly.