Positron scattering from simple molecules

Abstract

A modified version of spherical complex optical potential formalism is employed to calculate the positron scattering cross sections over a wide energy range from near positronium formation threshold to 5000 eV. In the present study, the interaction potential of the positron-target scattering system is developed under an optical potential framework for the calculation of positron scattering total cross sections for CH 4 , CO, CO 2 , H 2 , N 2 O and NO molecules. The results obtained are in good agreement with most of the available experimental and theoretical values in terms of its shape and magnitude. A characteristic increase in cross section is observed for all the molecules near the positronium formation threshold, which signifies the emergence of positronium formation along with other inelastic channels.

A Theoretical Study of Scattering of Electrons and Positrons by CO2 Molecule

“…In the independent atom model approximation, the effective atomic polarizability defined by Equation ( 24) is used to calculate the polarization potential V p (r) for an atom. The values of first molecular excitation energy and ionization potential are 11.04 eV [3] and 13.773 eV [42] for the present analysis.…”

“…Projectile-atom/molecule scatterings are very common in many natural and manmade systems, such as gaseous plasma [1], planetary atmospheres [2], radiation chemistry [3], radiobiology [3], mass spectrometry [4], etc. Accurate data of various observables of such scattering phenomena are, therefore, of crucial importance for the enhancement of our knowledge about the science of planetary, stellar, and interstellar spaces and for the development of technologies.…”

“…Campeanu et al [28] predicted the same observable for E i = 20-1000 eV using the CPE (Coulomb plus plane waves with full energy range) distorted wave model. Recently, Singh et al [3] reported a TCS calculated over a wide energy range (threshold to 5000 eV) using a modified version of the SCOP.…”

Theoretical study of positron scattering by group 14 tetra hydrides: A quantum mechanical approach

“…Hence, it is vital to study the interaction of these molecules with positrons. A modified form of the quantum mechanical approach, namely the SCOP and CSP‐ic formalism has been implemented in the present work to calculate the direct ionization, Ps formation, total ionization and total cross section for positron‐ XH 4 scattering. The calculation is done for an extensive energy range of 1 eV to 5 keV for the present set of molecules, viz.…”

“…The present XH 4 targets have tetrahedral structure and belongs to T d point group. The close packed structure of the molecules has prompted us to employ the modified spherical complex optical potential (SCOP) formalism [45][46][47][48] using the method of single center expansion (SCE) technique. [49] In this method, we have expanded the charge density of the lighter hydrogen atom from the center of the heavier group 14 element.…”