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Dissociative electron attachment (DEA) is one of the processes that shows a strong coupling between the nuclear and electronic degrees of freedom in a molecule. This coupling results in an efficient transformation of the kinetic energy of attaching free electrons into the chemical energy of the compound molecule. A recent discovery of quantum coherence in this process has opened a whole new dimension in its description. On the other hand, the mass variation in isotopes of the constituent atoms has a profound effect on DEA. In quantum coherence observed in DEA, the isotope effect depicts itself in terms of change in the phase and the amplitude of the interfering dissociation paths. Here, we report the quantum coherence observed in DEA to HD, an isotopologue of H$_2$. In this isotopologue, both H$^-$ and D$^-$ show identical forward-backward asymmetry in the angular distribution. We explain these findings using the interference between two quantum paths, with the permanent dipole moment of the asymmetric mass playing no role in the process.

One of the most challenging and recurring problems when modelling plasmas is the lack of data on key atomic and molecular reactions that drive plasma processes. Even when there are data for some reactions, complete and validated datasets of chemistries are rarely available. This hinders research on plasma processes and curbs development of industrial applications. The QDB project aims to address this problem by providing a platform for provision, exchange, and validation of chemistry datasets. A new data model developed for QDB is presented. QDB collates published data on both electron scattering and heavy-particle reactions. These data are formed into reaction sets, which are then validated against experimental data where possible. This process produces both complete chemistry sets and identifies key reactions that are currently unreported in the literature. Gaps in the datasets can be filled using established theoretical methods. Initial validated chemistry sets for SF$_6$/CF$_4$/O$_2$ and SF$_6$/CF$_4$/N$_2$/H$_2$ are presented as examples., Comment: 30 pages, 7 figures, 10 tables

In this paper, we discuss the dissociative electron attachment process in Formic Acid and Propyl Amine. These are molecules containing more than one functional group and have low symmetry (Cs group). We measured the kinetic energy and angular distributions of fragment H^{-} ions from the resonances observed in these molecules and compared with that in the precursor molecules, namely - Water, Ammonia and Methane. Measurements suggest that the dissociation dynamics in bigger molecules are independent of overall symmetry of the molecule, rather depend only on the local symmetry of functional group and bond orientation factors., Comment: 13 pages, 7 figures

In the present paper, we report the details of the kinetic energy and angular distributions of the H^{-}, S^{-}/SH^{-} fragment ions produced due to dissociative electron attachment in H_{2}S molecules at resonances peaking at 2.2 eV, 5.2 eV, 7.5 eV and 10 eV., Comment: 18 pages, 11 figures

In this paper, we discuss the dissociative electron attachment process in Methane. Kinetic energy and angular distributions of H^{-} and CH_{2}^{-} fragment anions across the broad resonance about 10 eV is reported. Angular distribution of H^{-} ions changes from being perpendicular to forward-backward scattering across the resonance. Possibility of Jahn-Teller effect on excitation of the triply degenerate 1t2 molecular orbital is inferred., Comment: 14 pages, 8 figures

In this paper, we discuss the dissociative electron attachment process in Ammonia. Kinetic energy and angular distributions of H^{-} and NH_{2}^{-} fragment anions across the two well known resonances at 5.5 eV and 10.5 eV are reported. The angular distributions show deviation of axial recoil approximation akin to that observed in water., Comment: 18 pages, 10 figures

Using the velocity map imaging technique, we studied and characterized the process of Dissociative Electron Attachment (DEA) in polyatomic molecules like Water, Hydrogen Sulphide, Ammonia, Methane, Formic Acid and Propyl Amine. We present the details of these studies in a series of 5 articles. In the first article here, we discuss the DEA process in gas phase water ($H_{2}O$ and $D_{2}O$) molecules. Electrons of 6.5 eV, 8.5 eV and 12 eV are captured by water molecules in neutral ground state to form $H_{2}O^{-*}$ ($D_{2}O^{-*}$) resonant states which dissociate into an anion fragment and one or more neutrals. Kinetic energy and angular distributions of the fragment anions $H^{-}$($D^{-}$) and $O^{-}$ produced from the three negative ion resonant states in the entire $2\pi$ scattering range are obtained. Unique angular distribution patterns are observed at the 8.5 eV and 11.8 eV resonances showing dissociation dynamics beyond the axial recoil approximation., Comment: 40 pages, 14 figures, More detailed version of the journal paper - J. Phys. B : At. Mol. Opt. Phys. 42, 225203 (2009)