New ab initio potential energy surfaces for the F+H2 reaction

We present the results of new ab initio calculations of the three FH2 potential energy surfaces (PESs) which are necessary for a complete description of the F+H2 reaction. These are the result of high-precision multireference configuration-interaction calculations, with an additional scaling of the external correlation energy. The results of these calculations have been fitted to a multiparameter form for use in subsequent quantum scattering calculations. With a scaling factor of s=1.078, the calculated exoergicity agrees nearly exactly with experimentally determined values. With a slightly reduced scaling factor of s=1.05, the fitted PESs give excellent agreement with the position and modulation depth of the F+HD-->FH+D transition state resonance observed by Skodje et al. J. Chem. Phys. 112, 4536 (2000). This suggests that these new PESs can be used with confidence in the simulation of the reactivity of the ground and excited spin-orbit states of the F atom in reactions with H2.