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 $\mathrm{F}+{\mathrm{Li}}_2\to \mathrm{LiF}+\mathrm{Li}$ . 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 $\mathrm{F–Li–Li}$ , this complex is bound by 4 kcal/mole relative to separated LiF + Li. The attraction is much stronger, 34 kcal, for C_2v geometry, and this species is predicted to have a bond angle of 99° and $\mathrm{Li–F}$ bond distance of 1.79 Å. Several excited electronic states of FLi₂ are discussed briefly.