On the valence bond diatomics-in-molecules method. II. Application to the valence states of FH2

Abstract

Explicit methods are given for setting up the matrices involved in the projector approach of the preceding paper to the diatomics-in-molecules (DIM) method for obtaining potential energy surfaces. Application is made to the 14 spin–orbit surfaces of the FH2 system produced from the consideration of only the valence electrons on the atoms and ’’ionic–covalent’’ coupling in the HF diatomic fragment. This FH2 example contains an illustration of each type of complication one could encounter in the use of the DIM method as a semiempirical technique. Plots of the ground state spin–orbit FH2 surface are given along C∞v ’’abstraction’’, C2v, Cs, and C∞v ’’exchange’’ cuts, as well as reactant to product correlation energy diagrams produced from vertical cuts along minimum energy pathways of these symmetries. Comparison is made to existing information whenever possible.