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Low energy (around <15 eV electron energy)
electron-molecule collisions leading to dissociative electron
attachment (DEA) is an important process from the fundamental as well
as the application point of view. DEA is a two-step resonant process
resulting into a final anionic and neutral fragment from a parent
neutral molecule via intermediate negative ion state. DEA study of
molecules are very important starting from electrical discharges,
atmospheric chemistry, installer medium chemistry to radiation induced
damage of living cell and biologically important molecules. Due to
resonant nature, site-specific fragmentation is unique to DEA process.
These methods can be used in site selective bond cleavage in DNA.
Dipolar dissociation is another process that occurs slightly higher
incident electron energy compared with DEA, is also equally important
in radiation damage, atmospheric chemistry and installer medium
chemistry.
In these context, a time sliced velocity map imaging spectrometer has
been developed implementing state-of-the-art technologies for the
study of low-energy electron-molecule collision processes:
particularly, dissociative electron attachment (DEA) and dipolar
dissociation (DD). Using the spectrometer both kinetic energy and
angular distribution of the fragment ions can be measured
simultaneously and accurately over the entire 2\pi angle. My PhD work
includes the development of velocity slice imaging spectrometer and
its application by performing kinematically complete measurements on
DEA to simple molecules like CO, Cl2, CO2 and DD to O2.
In this talk, I will describe the spectrometric technique in details
and some of the interesting results obtained and finally, the future
directions.
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