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Cold Electron Chemistry in the Gas Phase: Benchmark Experiments David Field Department of Physics and Astronomy, Ny Munkegade,
Building 520, University of Aarhus A great deal of interest is focussed at present on cold scattering encounters, in which the wavelength of the projectile is very much greater than the physical dimensions of the target. We consider here electrons of a few to a few tens of meV (1), whose wavelengths are of the order of 10 nm, impinging on molecules whose dimensions are less than 1nm. Strong quantum effects are very apparent in the scattering. In this presentation I concentrate upon virtual state effects in molecules such as C6F6 and the application to CCl4 and SF6 of a method which allows the determination of absolute cross-sections for attachment of cold electrons without recourse to rate constant data. Recent experimental work has demonstrated that the phenomenon of virtual state scattering can lead to very large scattering cross-sections in very low energy encounters. These experiments will be described (1) and data shown for a number of species including C6F6 and other species (2,3,4). The qualitative nature of virtual state scattering will be discussed, in terms of nuclear adiabatic and diabatic channels. Implications of results for both industrial and naturally occurring
plasmas, such as the interstellar medium, will be discussed. References |
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