Schematic diagram of the apparatus. The inset shows a representative distribution of final energies typical of ion pairs formed in collisions between low- Rydberg atoms and attaching targets together with the field induced dissociation thresholds associated with and plus (see text).
Calculated survival probabilities for ion-pair states with and the values of indicated in a ramped field applied at that rises linearly from 0 to in . For each value of , a random distribution of values of in the range of is assumed. The simulations also assume a pure Coulomb interaction between the ions.
Ion arrival time distributions for ions produced in collisions at a Rydberg atom velocity of . Rydberg excitation defines and the initial pulse is applied after a collision time of . Data are included for applied following the additional time delays, , indicated.
Time development of the populations of (a) , (b) , and (c) ion-pair states having binding energies in the ranges (●) 5–12 meV, (○) 18–23 meV, (◼) 29–34 meV, and (◻) 44–48 meV. The solid lines show exponential fits to the data and correspond to the lifetimes indicated.
Rydberg-atom velocity dependence of the measured rate for direct production of (a) free ions in collisions and (b) free ions in K(16p)–BrCN collisions. The dashed lines show the predictions of Monte Carlo simulations that assume no internal-to-translational energy transfer. The experimental data are normalized to the simulations.
Arrival time distributions of (free) ions produced through K(16p)–BrCN collisions at the Rydberg atom velocities indicated. The origin of the time axis is taken to be the end of the 200-ns-long laser excitation pulse. The various data sets are normalized to the same maximum value.
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