The focus of our research work is on studying the scattering of positrons
(antiparticles of electrons) and electrons from various atoms and molecules.
Atomic and molecular collision processes play important and significant role in
aeronomy, astrophysics, combustion physics, plasma physics and a number of other
areas. We calculate the cross sections for various scattering processes using a
variety of theoretical techniques. The target systems under current
investigation for calculating the cross sections include rare gas atoms, alkali
atoms and light molecules. The atomic processes under consideration include
elastic, inelastic (including ionization) and rearrangement collisions of
electrons and positrons. In particular, we have also calculated, and compared
with experiments, the cross sections for the ionization of inner shells of
various atoms by impact of both positrons and electrons.
Other research interests include investigations of production of negative
ions by the process of dissociative electron attachment to simple molecules. The
rates of negative ion production by this process are strongly enhanced if the
attaching molecule is initially rovibrationally excited. We have also calculated
the cross sections for the vibrational excitation and dissociation of simple
molecules by electron impact. For the calculations of cross sections for the
processes of dissociative electron attachment, vibrational excitation and of
dissociation, we use the non local resonance theory that invokes the
formation of the molecular anion resonant state as an intermediary.
Various cross sections that we calculate are used for investigating the
transport of charged particle swarms through various pure gases or gas mixtures.
Using techniques that we have developed for obtaining exact numerical solutions
of the Boltzmann equation we can compare the transport properties of electron
swarms moving through a gaseous mixture subjected to external electric fields
with the corresponding properties of positron swarms. Such comparative studies
allow us to 'manufacture', on a computer, new gaseous materials which have
predefined electron and positron transport properties.