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MPINP:
Quantendynamik - Abteilung Blaum
Abstract:
We have investigated the autodetachment of electrons from rovibrationally hot SF6− anions using a cryogenic ion-beam trap. Extremely low residual gas densities of 104 cm−3 provided undisturbed observation of the neutralization rates due to vibrational autodetachment (VAD) over almost five orders of magnitude and over times up to 100 ms. We successfully explain our experimental decay curves using statistical rate theory combined with electron attachment data and vibrational frequencies calculated for a C4v -distorted SF6− . The unprecedented sensitivity of the experiment to the decay constants at the VAD threshold allows us to infer from the data the adiabatic electron affinity of SF6 to be (0.91±0.07) eV and to confirm the recently predicted C4v symmetry of SF6− .
