Experimental and theoretical cross sections for positron scattering from the pentane isomers

Abstract

Isomerism is ubiquitous in chemistry, physics, and biology. In atomic and molecular physics, in particular, isomer effects are well known in electron-impact phenomena; however, very little is known for positron collisions. Here we report on a set of experimental and theoretical cross sections for low-energy positron scattering from the three structural isomers of pentane: normal-pentane, isopentane, and neopentane. Total cross sections for positron scattering from normal-pentane and isopentane were measured at the University of Trento at incident energies between 0.1 and 50 eV. Calculations of the total cross sections, integral cross sections for elastic scattering, positronium formation, and electronic excitations plus direct ionization, as well as elastic differential cross sections were computed for all three isomers between 1 and 1000 eV using the independent atom model with screening corrected additivity rule. No definitive evidence of a significant isomer effect in positron scattering from the pentane isomers appears to be present.

Positron scattering from simple molecules

“…Positron scattering cross sections or calculated interaction parameters also find practical application in energy deposition models [7]. There have been many recent studies on positron scattering from biological molecules [8][9][10][11].…”

Elastic electron scattering from ortho-, meta-, and paraxylenes, C8H10

“…They found the three isomers behaved similarly, however since their work is not differential in angle, we expect that it is possible to see differences between these isomers for differential electron scattering from these isomers. A quite complete survey on electron and positron collisions with isomers of hydrocarbons and isomers of other molecules can be found in [11].…”

Study of Electron Collisions with Isoprene, 1,2-Butadiene, and Their Isomers

“…We further demonstrated that the bonding effect, chain length (closed or open), and atom layout within a molecular target all have an effect on scattering. To explore these effects thoroughly, we studied the isomers 23 of isoprene and 1,2-butadiene.…”