The excitation function for Li+HF-->LiF+H at collision energies below 80 meV

We have measured the dependence of the relative integral cross section of the reaction Li+HF-->LiF+H on the collision energy using crossed molecular beams. By varying the intersection angle of the beams from 37{\deg} to 90{\deg} we covered the energy range 25 meV < E_tr < 131 meV. We observe a monotonous rise of the cross section with decreasing energy over the entire energy range indicating that a possible translational energy threshold to the reaction is significantly smaller than 25 meV. The steep rise is quantitatively recovered by a Langevin-type excitation function based on a vanishing threshold and a mean interaction potential energy ~R^-2.5 where R is the distance between the reactants. To date all threshold energies deduced from ab-initio potentials and zero-point vibrational energies are at variance with our results, however, our findings support recent quantum scattering calculations that predict significant product formation at collision energies far below these theoretical thresholds.Comment: 8 pages, 7 figure

Entwicklung und Erprobung eines neuartigen zeit- und ortssensitiven Detektors zur Laserdiagnostik von chemischen Reaktionen und Analyse von Fluoreszenzlebensdauern, 3D-Teilchenspuren und Entfernungen

Bobbenkamp R. Entwicklung und Erprobung eines neuartigen zeit- und ortssensitiven Detektors zur Laserdiagnostik von chemischen Reaktionen und Analyse von Fluoreszenzlebensdauern, 3D-Teilchenspuren und Entfernungen. Bielefeld; 2001

Dynamics of the insertion reaction C(1D)+ H2: A comparison of crossed molecular beam experiments with quasiclassical trajectory and quantum mechanical scattering calculations

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