Positron driven molecular processes for H2CO, NO2 and HCN

Abstract

In this work, we report results of comprehensive study of positron driven molecular chemistry for planetary compounds, H₂CO, NO₂ and HCN. All these molecules are highly polar in nature making the positron-molecule interaction more sensitive to polarization potential at lower energies. We have employed a novel approach to construct the polarization potential that takes Positron Correlation Polarization (PCP) to determine the energy independent cut-off thereby properly accounting for the short range effects. We have quantified various molecular processes initiated due to positron interaction by evaluating elastic ($Q_{el}$), inelastic ($Q_{inel}$), direct ionization ($Q_{D-ion}$), positronium formation ($Q_{Ps}$), total ionization ($Q_{ion}$) and total cross-sections ($Q_{tot}$) for the wide energy span from circa 1 eV–5000 eV using modified Spherical Complex Optical Potential (SCOP) method. Positron driven ionization is investigated using Complex Scattering Potential – ionization contribution (CSP-ic) method. In this work, positronim formation and direct ionization channels are reported for the first time, except for H₂CO. This study aims to find probabilities for different positron assisted processes for these molecules using the quantum chemical treatment that can contribute to improve various models of atmospheric chemistry.