Electron-induced reactions

Rossi, 1983), light-induced and solvated-electron-induced reactions (Bun-nett, 1978), electrochemical induction (Saveant, 1980a), synthetic aspects (Beugelmans, 1984 Norris, 1990 Wolfe and Carver, 1978), photochemical induction of the reaction at heteroaromatic carbon centres (Lablache-Combier, 1988). There is no point in repeating here the extensive lists of reactions contained in these review articles. We shall just underline a few points and report recently available findings. 

Impact of LEE on atomic and molecular solids has been observed to induce chemical changes other than dissociation. In the next two sections, we will review examples of electron-induced reactions that proceed via formation of a TNI. 

Electron-Induced Reactions—HREELS Measurements. Novel LEE-induced chemistry has also been observed in HREEL measurements of molecular solids and molecules physisorbed on the surface of RGS. For example, Lepage et ah, building on the initial observations of Jay-Gerin et al. [141], have employed HREELS to measure in situ, neutral dissociation products arising from the impact of low-energy electrons on thin multilayer films of methanol [37] and acetone [38]. The technique is similar to that developed earlier by Martel et al. [258] for chemisorbed systems, in that the same electron beam is used for both the production and the detection of the neutral fragments. However, in the work of Lepage... 

Bombardment of polymers by electrons causes bond breakage. The free radical or ionic sites thus generated activate subsequent scission or cross-linking reactions. Because all polymers are susceptible to electron-induced reactions, essentially any material can, in principle, function as a resist. 

Since there have been no previous studies of spin-polarized electron induced reaction asymmetries in adsorbed chiral molecules, the exact manner by which the enhancement occurs is unclear. If the orbital occupied during DEA is sufficiently diffuse so as to sample the regions of the molecule responsible for the chiral structure [92] then enantiomeric specific dissociation will result. On the other hand, it has been theorized that two enantiomers will be ionized at different rates by longitudinally spin-polarized electrons [126]. If there are sufficient numbers of higher energy spin-polarized secondary electrons and the final state reached following ionization is dissociative, then this could lead to chiral enhancement. 

Arumainayagam CR, Lee H-L, Nelson RB et al (2010) Low-energy electron-induced reactions in condensed matter. Surf Sci Rep 65 1 —44... 

Figure 3 Schematic of ion molecule reactions induced by radiation in the interstellar medium, "e" indicates an electron-induced reaction.

FIGURE 16.2 Schematic potential energy curves showing electron attachment, electron autodetachment, and DEA for a TMA. (Surf. Sci. Rep., 65, Arumainayagam, C.R., Lee, H.L., Nelson, R.B., Haines D.R., and Gunawardane, R.P., Low-energy electron-induced reactions in condensed matter, 1-44, Copyright 2010, with permission from Elsevier.)... 

Overall, this study carried out in Polanyi s group demonstrates that Br-Si(s) is the product of photoreaction. Since the reaction product forms at the Si atom beneath the parent CH3Br(ad), a localized photoreaction is produced. The localized nature of the bromination also occurs for the electron-induced reaction, in which the CH3Br(ad) is found to react to form a ring pattern like that obtained for the photoreaction (panel (f) in Figure 29.13). However, in this case the ring appears only partial, since the pattern was obtained from a single scan. 

This interesting study of the photo- or electron-induced reaction of a SA monolayer of CHaBr at a (crystalline) Si surface suggests powerful possibilities for imprinting nano-patterns (e.g. Jacoby, 2004). In the view mediated in said summary, surface reactions can be classified as having parent-mediated or daughter-mediated dynamics... 

Q.-B. Lu, Phys. Rep., 487,141-167 (2010). Cosmic-Ray-Driven Electron-Induced Reactions of Halogenated Molecules Adsorbed on Ice Surfaces Implications for Atmospheric Ozone Depletion and Global Climate Change. 

J.-U. GrooE andR. Muller, Armos. Environ., 45,3508-3514 (2011). Do Cosmic Ray-Driven Electron-Induced Reactions Impact Stratospheric Ozone Depletion and Global Climate... 

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