Electron- and positron-driven molecular processes for H2O, CO2, and NH3 in their gas and ice phases.

In this comprehensive study, we explored the molecular chemistry of H2O, CO2, and NH3 molecules in their gas and ice phases assisted by electron and positron interactions over a wide range of energy from threshold to 5000 eV. These simple molecules have immense applications in areas such as atmospheric sciences and astrochemistry. We employed the spherical complex optical potential (SCOP) model along with the complex scattering potential-ionization contribution (CSP-ic) model and modified them to quantify the probabilities of various charged particle-driven molecular processes through inelastic cross-sections (Qinel), total ionization cross-sections (Qion), direct ionization cross-sections (QD-ion), and positronium formation cross-sections (QPs) for these molecules in gas and ice phases. We propose a novel model that incorporates the band gap of a material for positron impact cross-sections with molecules in their condensed phase. This is the first study on electron interactions with NH3 (ice) and positron interactions with H2O, CO2, and NH3 in their condensed phase.

Electron interaction with DNA constituents in aqueous phase.

Electron driven chemistry of biomolecules in aqueous phase presents the realistic picture to study molecular processes. In this study we have investigated the interactions of electrons with the DNA constituents in their aqueous phase in order to obtain the quantities useful for DNA damage assessment. We have computed the inelastic mean free path (IMFP), mass stopping power (MSP) and absorbed dose (D) for the DNA constituents (Adenine, Cytosine, Guanine, Thymine and Uracil) in the aqueous medium from ionisation threshold to 5000 eV. We have modified complex optical potential formalism to include band gap of the systems to calculate inelastic cross sections which are used to estimate these entities. This is the maiden attempt to report these important quantities for the aqueous DNA constituents. We have compared our results with available data in gas and other phase and have observed explicable accord for IMFP and MSP. Since these are the first results of absorbed dose (D) for these compounds, we have explored present results vis-a-vis dose absorption in water.