Functional Group Dependent Site Specific Fragmentation of Molecules by Low Energy Electrons

Functional group dependence is observed in the dissociative electron attachment (DEA) to various organic molecules in which the DEA features seen in the precursor molecules of the groups are retained in the bigger molecules. This functional group dependence is seen to lead to site-selective fragmentation of these molecules at the hydrogen sites. The results are explained in terms of the formation of core-excited Feshbach resonances. The results point to a simple way of controlling chemical reactions as well as interpreting the DEA data from bigger biological molecules.

Figure 1

${\mathrm{H}}^{-}$ ion yield curve from (a) acetic acid and (b) propanoic acid.

Figure 2

${\mathrm{H}}^{-}$ and ${\mathrm{D}}^{-}$ ion yield curves from ${\mathrm{CH}}_3\mathrm{COOH}$ and ${\mathrm{CH}}_3\mathrm{COOD}$: (+) ${\mathrm{H}}^{-}$ from ${\mathrm{CH}}_3\mathrm{COOH}$, (▲) ${\mathrm{D}}^{-}$ from ${\mathrm{CH}}_3\mathrm{COOD}$, (□) ${\mathrm{H}}^{-}$ from ${\mathrm{CH}}_3\mathrm{COOD}$. The lines joining the points are for guiding the eye.

Figure 3

Ion yield curves of ${\mathrm{H}}^{-}$ from (a) ${\mathrm{CH}}_3\mathrm{OH}$ and (b) ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$.

Figure 4

Ion yield curve of ${\mathrm{H}}^{-}$ from $n$-propyl amine.