Study of inelastic channels by positron impact on simple molecules

Abstract

The present work concentrates on the investigation of various inelastic channels such as positronium (Ps) formation, direct ionization, and total ionization by the positron impact for simple molecules in an extensive energy range (∼Ps formation threshold to 5 keV). The modified form of the well-known spherical complex optical potential formalism and the complex scattering potential-ionization contribution method are used for the calculations. Although only limited literature was available for the molecules studied in the present endeavor, in general, reasonable agreement is found with the existing data. A phenomenological technique developed recently is used in the present work to calculate the Ps formation cross section efficiently.

Positron Scattering: Total Elastic and Grand Total Cross Sections for Molecules of Astrophysical Importance

“…The cross sections of Baluja and Jain lie consistently below present results. A similar behaviour was observed in our previous work too . Authors have used additivity rule and simply added the cross sections of the constituent atoms to give the cross sections for the molecule.…”

“…We have carried out the computation of elastic and grand total cross sections for the astrophysical molecules, namely H 2 O, N H 3 , HCl, OCS and SO 2 using the modified SCOP formalism . The cross sections obtained are compared with the existing data in the literature.…”

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

“…Using this method the total elastic ( Q el ) and total inelastic ( Q inel ) cross sections are calculated which is finally summed up to give the total cross section ( Q tot ). Modified complex spherical potential‐ionization contribution (CSP‐ic) method is then used to compute the ionization cross section from the inelastic cross section. The target properties of the molecules employed in the calculation are given in Table .…”

“…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.…”

“…Modified complex spherical potential-ionization contribution (CSP-ic) method [47] is then used to compute the ionization cross section from the inelastic cross section. The target properties of the molecules employed in the calculation are given in Table 1.…”