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.