Sumona Gangopadhyay

Electron collisions with sulfur compounds SO, SO2 and SO2AB (A, B = Cl, F): various total cross sections

This paper reports our theoretical investigations into electron scattering with SO, SO2, SO2Cl2, SO2ClF and SO2F2 in the energy range from the ionization threshold to 2000 eV. The present studies are prompted by the occurrence and applications of these molecular species in atmospheric and astrophysical systems, together with a paucity of data for SO and SO2AB (A, B = Cl, F) species. Complex model potential calculations are carried out to find total elastic as well as inelastic cross sections, and ionization cross sections are retrieved from inelastic cross sections in a semi-empirical approximation. Comparisons with other data are made and discussed.

Electron impact ionization of water molecules in ice and liquid phases

Electron scattering processes in ice or water are known to occur in natural as well as man-made systems. But the processes are difficult to investigate in theory or in laboratory. We present our calculations on total ionization cross section (Qion) for collisions of electrons with H2O molecules in condensed matter (ice and liquid) forms, at impact energies from ionization threshold to 1000 eV, extendable to about 1 MeV. Our theoretical method determines the total inelastic cross section (Qinel) of electron impact on H2O (ice), by starting with the complex scattering potential partial wave formalism. Reasonable approximations are invoked to project out the ionization cross section of H2O molecule in ice (or liquid) form by using the Qinel as an input. Properties of the condensed phase H2O are incorporated together with bulk screening effects in the scattering echanism. Due to medium effects, the present Qion are found to be lower than the corresponding values for H2O in free or gaseous state. Macroscopic cross sections and electron mean free paths for the bulk medium are also calculated. This study has potential applications in radiation biology as well as chemistry and in planetary science and astrophysics.

Calculations on various total cross-sections of electron impact on group VA - Atoms-Threshold to 2000 eV

Synopsis In this paper we have calculated various total cross-sections of Nitrogen, Phosphorus, Arsenic, Antimony and Bismuth (Group VA-atoms) in the energy range of 15 to 2000 eV. Spherical Complex potential formalism is used to derive total as well as inelastic cross-sections. We have developed CSP-ic method by which we can extract ionization cress-section from the inelastic cross-section. Our results are compared with available theoretical and experimental data.