Potassium Rydberg atoms are used to investigate the lifetimes, on a picosecond timescale, of transient negative ions formed during dissociative electron attachment to CCl$\sb4$ and CF$\sb3$I. The transient negative ions are formed during Rydberg electron transfer reactions of the type$${\rm K}(n{\rm p})+AB\to{\rm K}\sp{+}+AB\sp{-*}\to{\rm K}\sp{+}+A\sp{-}+B$$For low values of principal quantum number $n\ (n\ \sbsp{\sim}{<}\ 20)$ the electrostatic interaction between the ${\rm K}\sp{+}-AB\sp{-*}$ and ${\rm K}\sp{+}+A\sp{-}$ ion pairs perturbs the ion trajectories. As a consequence, the final angular and velocity distributions of the ${\rm K}\sp{+}+A\sp{-}$ ions are dependent on the lifetime of the $AB\sp{-*}$ intermediate ion. The $AB\sp{-*}$ lifetime is determined by comparing product ion distributions, determined using position sensitive detection techniques, with the results of a Monte Carlo simulation that models the kinematics of the reaction. The data show that the lifetime of the excited $\rm CF\sb3\Gamma\sp{*}$ intermediate formed by Rydberg electron capture is short, $\sbsp{\sim}{<}2$ ps, and that the lifetime of the CCl$\sbsp{4}{-*}$ intermediate is $7.5\pm2.5$ ps.
| Identifer | oai:union.ndltd.org:RICE/oai:scholarship.rice.edu:1911/16993 |
| Date | January 1996 |
| Creators | Popple, Richard Allen |
| Contributors | Dunning, F. B. |
| Source Sets | Rice University |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 102 p., application/pdf |
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