How to observe the elusive resonances in F + H2 reactive scattering

Time-dependent wavepacket calculations have been used to simulate the photoelectron spectrum of the FH2− anion at the high energy resolution attainable in anion threshold photodetachment experiments, using the new ab initio potential energy surface of Stark and Werner. In addition to the direct scattering F + H2 hindered-rotor states that have been seen in earlier spectra at lower resolution, the present high-resolution spectra show a distinct set of narrow peaks due to quantum mechanical reactive scattering resonances. These resonances have not been detected previously in any other F + H2 reactive scattering experiment.