Dynamics of dissociative electron attachment to aliphatic thiols

Dissociative electron attachment (DEA) shows functional group-dependent site selectivity in H- ion channels. In this context, thiol functional groups have yet to be studied in great detail, although they carry importance in radiation damage studies where low-energy secondary electrons are known to induce damage through the DEA process. In this context, we report detailed measurements of absolute cross-sections and momentum images of various anion fragments formed in the DEA process in simple aliphatic thiols. We also compare the observed dynamics with that reported earlier in hydrogen sulphide, the precursor molecule for this functional group, and with that in aliphatic alcohols. Our findings show substantial resemblance in the underlying dynamics in these compounds and point to a possible generalisation of these features in the DEA to thiols. In addition, we identify various pathways that contribute to the S- and SH- channels.

Dynamics of the Dissociating Uracil Anion Following Resonant Electron Attachment

We report a combined experimental and theoretical investigation of dissociative electron attachment (DEA) to the nucleobase uracil. Using ion momentum imaging experiments employing a DEA reaction microscope we have measured 3-dimensional momentum distributions of specific anionic fragments following DEA to uracil by 6 eV electrons. From the measured anion fragment kinetic energy we determine the possible dissociation pathways and the total kinetic energy release. We employ electronic structure and electron scattering calculations to determine the probability for electron attachment in the molecular frame. Combining these calculations with the imaging measurements, we reveal several key features of the coupled electronic and nuclear dynamics of DEA.

Dissociative electron attachment to N2O using velocity slice imaging

The structure and dynamics of the negative ion resonances leading to dissociative electron attachment in N2O are studied using the velocity slice imaging technique. Distinct momentum distributions are observed in the O(-) channel for the dominant resonances below 4 eV which are considerably different than those reported so far. Also the relatively weak but distinct resonances at 8.1 eV and 13.2 eV are studied for their dynamics for the first time. For each of these resonances two different channels of dissociation are observed with differing angular distributions.