Dissociative electron attachment reactions of the type K(nd) + AB $\to$ K$\sp+$ + AB$\sp{-*}$ $\to$ K$\sp+$ + A$\sp-$ + B have been investigated for polyatomic molecules BrCN, CF$\sb2$Br$\sb2$, CF$\sb3$Br and Fe(CO)$\sb5$. Rate constants for the formation of various negative ions were measured for a range of principal quantum numbers n. At high n (n $>$ 40), the Rydberg electron can be treated as 'essentially' free electron and the present data are compared with the free electron data obtained by the TPSA technique. At lower n, the free electron model must be modified to take into account post-attachment electrostatic interactions between the product ions and effects associated with the reduced size of the Rydberg atom.
The translational energy release in such reactions was measured using the TOF-PSD technique. Comparison with the excess energy of reaction for BrCN and CF$\sb2$Br$\sb2$ shows that the energy released by electron capture is well distributed among the internal modes of the intermediate negative ion prior to dissociation. In contrast, data for CF$\sb3$Br indicate that the electron capture takes place into a repulsive state resulting in the immediate dissociation of the intermediate negative ion before significant redistribution of excess energy can occur.
| Identifer | oai:union.ndltd.org:RICE/oai:scholarship.rice.edu:1911/16580 |
| Date | January 1992 |
| Creators | Marawar, Ravindra Wamanrao |
| Contributors | Dunning, F. B. |
| Source Sets | Rice University |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 83 p., application/pdf |
Page generated in 0.218 seconds