Abstract
We investigate the effect of near threshold resonances in reactive scattering at low energy. We find a general type of anomalous behavior of the cross sections, and illustrate it with a real system (). For inelastic processes, the anomalous energy dependence of the total cross section is given by (with ). The standard threshold behavior given by Wigner's law () is eventually recovered at vanishing energies, but its validity is now limited to a much narrower range of energies. The anomalous behavior leads to reaction rate coefficients behaving as instead of the expected constant rate of the Wigner regime. We also provide analytical expressions for -wave cross sections, and discuss the implication in ultracold physics and chemistry.
- Received 20 September 2013
- Revised 20 March 2014
DOI:https://doi.org/10.1103/PhysRevA.89.040701
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