Reactivity enhanced by under-barrier tunneling and resonances:the F+ + H2 -- HF + H reaction

Rate costants for the prototypal process are calculated by an essentialy exact(all partial waves) algorithm in the 10-350 K temperature range, where the reaction proceeds mainly by tunneling and is found to be enhanced by quantum resonances. Improving on the state-of-the-art ab-initio potential energy surface by an accurate description of the entrance channel according to our previous molecular-beam scattering experiments brings theory for the first time in agreement within mutual uncertainties with available experimental data, showing a non-Arrhenius behavior and permitting a quantitative assessment of features of chemical reactivity in the currently extensively cold(and possibly ultracold) regimes