Low energy electron (< 20 eV) molecule interaction has been studied ever since the discovery of electrons. It is relevant to a wide range of processes in plasma physics, astrochemistry, atmospheric chemistry, and radiation biology. These include dissociative electron attachment, neutral dissociation, and dipolar dissociation, with the latter being more relevant beyond 15 eV energy. Remarkably, the dissociative electron attachment has been the most intriguing process, a significantly efficient process of transferring mechanical energy to chemical energy. The molecular dynamics underlying this process is challenging to model due to the inherent resonant nature of the states involved. We provide the experimental avenues to unravel these features. One such finding is the functional group-dependent site selectivity of dissociation, beyond the conventional threshold energy-based approach. Recently, we have discovered symmetry breaking and the role of quantum coherence in these processes. Our group is interested in unravelling these unknown facets of the low-energy electron molecule interactions and provide experimental inputs to understand these excited states of molecular anions and neutral autoionizing states.

Apart from the electron attachment to the ground state molecules, our group is also interested in electron attachment to the excited molecule. These target molecules can be electronically and/or vibrationally excited. The idea is to explore the extent of electron-induced control on molecular dissociation that one can manoeuver using the initial excitation of the target. For this purpose, we need to have enough population in the excited states. Therefore, our group is exploring various coherent control based schemes to generate molecular targets in their excited states.  We are also using the simple heating of the gaseous targets to explore these avenues.

One of the exciting prospects of the electron-molecule interaction is the possibility of controlling chemical reactions using free electrons. In this context, taking our understanding of the fundamental electron molecule interaction from the gas phase experiments, we explore the free-electron initiated reactions in the condensed phase. For this purpose, we have developed an experimental scheme that measures the electron-induced chemical changes in the molecular films deposited on the cold (10K) surfaces. These experiments have provided the first experimental evidence of the free electron’s catalytic behaviour, predicted earlier using theoretical calculations. We have also discovered the prominent role of electron impact neutral dissociation in activating the C-H bond in hydrocarbons.

Our group has pioneered the velocity slice imaging (VSI) based momentum imaging scheme for the processes arising from the low energy electron-molecule interactions. Our group is constantly improving these schemes by introducing newer concepts and adaptations from our earlier experience of charged particle optics. We have developed a supersonic molecular beam based VSI set-up. We have also developed a compact VSI set-up capable of magnifying the low momentum images of ions with low kinetic energies. However, using the magnetic field to collimate the electron beam strongly affects the transverse ion-trajectories. This effect distorts the image, and it becomes worse for the low mass ions. Moreover, the mass resolution of the VSI spectrometer also restricts the imaging of the heavier ions. To overcome these problems, we have developed a VSI set-up that has the magnetic field restricted to a small region in the spectrometer, allowing us to extend the flight-tube length and improve its working condition for the heavier ions.