Three-Body Attachment in O2 using Electron Beams
YALE UNIV NEW HAVEN CT MASON LAB
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The three-body attachment reaction in O2, e 2O2 yield O2- O2, is studied by electron beam techniques. Whereas swarm experiments show a smooth variation of the attachment coefficient with energy, the present electron beam experiment shows pronounced structure. The peaks of this structure occur at the positions of the vibrational levels of the O2 system, which serve as compound states and have been identified in a previous experiment. These compound states dominate the low-energy cross sections in O2. They can decay by autodetachment, thus accounting for the bulk of the vibrational cross sections in O2 at low energy alternatively, they can be stabilized by a subsequent collision, thus leading to the formation of stable O2. Thus the authors establish clearly that three-body attachment in O2 is a two-stage process and that the intermediate is a vibrationally existed state of O2. The authors also obtain the temperature dependence of the three-body attachment at higher pressures. The experimental observations are in excellent agreement with the theory of Chapman and Herzenberg.
- Atomic and Molecular Physics and Spectroscopy