A b i n i t i o and semiempirical study of multiple surfaces and their analytic continuation for collinear F(2P3/2, 2P1/2)+H2→FH+H

The potential energy surfaces for the 2Π and 2Σ states in the collinear H2+F(2P3/2,1/2) →HF+H reaction have been calculated with ab initio restricted Hartree–Fock (GRHF) and GRHF–CI (configuration interaction) methods. The 2Π state in the CI calculations exhibits a well in the entrance valley. The effects of spin–orbit interaction have been examined in terms of a 2×2 secular equation in which the experimental spin–orbit coupling constant for the fluorine atom is used. GRHF calculations for complex values of nuclear coordinates are carried out to locate complex intersection points. Furthermore, two sets of semiempirical potential energy surfaces are constructed to simulate GRHF and GRHF–CI results. Dynamical implications of these surfaces are discussed in terms of complex intersections and nonadiabatic coupling constants.