Triple-differential cross sections for (e,2e) electron-impact ionization dynamics of tetrahydrofuran at low projectile energy

Enliang Wang,Xiangjun Chen,Zhenpeng Wang,Alexander Dorn,Chao Ma,Xueguang Ren,Maomao Gong,Don Madison,Esam Ali

doi:10.1103/physreva.102.062813

Abstract

We study the triple-differential cross section (TDCS) for the electron-impact ionization of the highest occupied molecular orbital of tetrahydrofuran at a projectile energy ${E}_{0}=91\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$. The experimental data were measured using a reaction microscope, which covers a large part of the full solid angle for the secondary electron emission with energies ranging from 6 to 15 eV, and projectile scattering angles ranging from $\ensuremath{-}{10}^{\ensuremath{\circ}}$ to $\ensuremath{-}{20}^{\ensuremath{\circ}}$. The experimental TDCSs are internormalized across all measured scattering angles and ejected energies. They are compared with predictions from the multicenter distorted-wave (MCDW) approximation and a modified MCDW-Nee method which includes the postcollision interaction (PCI) using the Ward-Macek factor. Additional calculations were obtained using a molecular three-body distorted-wave (M3DW) approach which accounts for PCI in an exact treatment. Generally, the MCDW-Nee and M3DW models show better agreement with experiment than the MCDW calculations. This shows the importance of accounting for PCI for low-energy outgoing electrons in electron-impact ionization processes.

Highlights

Electron scattering on atoms and molecules is important in many areas of science and technology ranging from astrochemistry over atmospheric sciences to plasma physics [1,2,3]
The branching ratio of the C2 to Cs conformer is about 45% : 55% at room temperature, which is consistent with the previous studies [48]
We reported a comprehensive study of the electron-impact ionization dynamics of the highest occupied molecular orbital (HOMO) of THF molecules at a low projectile energy of 91 eV

Summary

Introduction

Electron scattering on atoms and molecules is important in many areas of science and technology ranging from astrochemistry over atmospheric sciences to plasma physics [1,2,3]. In medical radiation therapy damage to biological tissue is caused by the primary radiation or particle but to a large part by the abundant and low-energetic secondary electrons with energies typically below 100 eV. It is well established that these electrons play an important role in producing DNA lesions either indirectly, e.g., by producing reactive hydroxyl radicals from the radiolysis of water, or directly via excitation and ionization reactions and by electron attachment—all of which can initiate molecular bond breaking and subsequent dissociation [4,5,6,7,8,9,10]

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Results

Conclusion