The transition state of the F + H2 reaction

The transition state region of the F + [H.sub.2] reaction has been studied by photoelectron spectroscopy of FH??. New para and normal FH?? photoelectron spectra have been measured in refined experiments and are compared here with exact three-dimensional quantum reactive scattering simulations that use an accurate new ab initio potential energy surface for F + [H.sub.2]. The detailed agreement that is obtained between this fully ab initio theory and experiment is unprecedented for the F + [H.sub.2] reaction and suggests that the transition state region of the F + [H.sub.2] potential energy surface has finally been understood quantitatively.
The transition state plays a central role in chemical reaction dynamics (1). Asymptotically observable quantities such as integral cross sections and thermal rate constants often depend crucially on what happens [...]