Infrared spectroscopy of organic free radicals related to combustion processes
- Univ. of Wisconsin, Madison (United States)
The primary long-term goal of this work is to develop new techniques for measuring vibrational spectra of polyatomic neutral free radicals. The authors explore a variation of resonant two-photon ionization (R2PI) in which tunable {omega}{sub IR} excites the radical vibrationally and {omega}{sub UV} selectively ionizes only the vibrationally excited molecules. Development of the IR + UV R2PI experiment is underway. In the meantime, the authors have used optical R2PI and pulsed field ionization (PFI) detection to obtain new vibrational spectra of species such as the benzyl and phenylsilane cations. In benzyl, a great deal was learned about the vibronic coupling mechanism in the mixed q{sup 2}A{sub 2}-2{sup 2}B{sub 2} system near 450 nm by projecting the mixed states onto the manifold of cation vibrational states. In phenylsilane{sup +}, we find that the sixfold barrier to internal rotation of the silyl group is small (V{sub 6} = +19 cm{sup {minus}1}). We are beginning to understand the mechanisms of coupling of torsional states with vibration, overall rotation, and other electronic states. In addition, we are developing a new model of internal rotation in aromatic compounds based on Prof. Frank Weinhold`s natural resonance theory.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- OSTI ID:
- 139938
- Report Number(s):
- BNL-48923; CONF-9306172-; ON: DE93015758; TRN: 93:002191-0092
- Resource Relation:
- Conference: 15. combustion research contractors` meeting, Lake Harmony, PA (United States), 2-4 Jun 1993; Other Information: PBD: 1993; Related Information: Is Part Of Fifteenth combustion research conference; PB: 391 p.
- Country of Publication:
- United States
- Language:
- English
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Infrared spectroscopy of organic free radicals related to combustion processes
Silyl group internal rotation in [ital S][sub 1] phenylsilane and phenylsilane cation: Experiments and [ital ab] [ital initio] calculations