An (e, 2e + ion) study of low-energy electron-impact ionization and fragmentation of tetrahydrofuran with high mass and energy resolutions

Abstract

We study the low-energy (E0 = 26 eV) electron-impact induced ionization and fragmentation of tetrahydrofuran using a reaction microscope. All three final-state charged particles, i.e., two outgoing electrons and one fragment ion, are detected in triple coincidence such that the momentum vectors and, consequently, the kinetic energies for charged reaction products are determined. The ionic fragments are clearly identified in the experiment with a mass resolution of 1 amu. The fragmentation pathways of tetrahydrofuran are investigated by measuring the ion kinetic energy spectra and the binding energy spectra where an energy resolution of 1.5 eV has been achieved using the recently developed photoemission electron source. Here, we will discuss the fragmentation reactions for the cations C4H8O(+), C4H7O(+), C2H3O(+), C3H6(+), C3H5(+), C3H3(+), CH3O(+), CHO(+), and C2H3(+).

An (e, 2e+ ion) study of electron-impact ionization and fragmentation of tetrafluoromethane at low energies

“…The basic principles of a general reaction microscope have been described by Ullrich et al [60]. Details of the experimental method are described in one of our earlier studies [56]. Here, we provide a short description on the experimental setup used for the present set of measurements.…”

“…To perform these experiments, we used an advanced reaction microscope which is built especially for electronimpact ionization studies [56,60]. The basic principles of a general reaction microscope have been described by Ullrich et al [60].…”

“…The BE is the vertical transition energy required to ionize a particular electronic orbital [56][57][58].…”

Ion induced fragmentation cross-sections of DNA constituents

“…• C. The extended mass spectrum of Ren's publication [30] indeed shows a 5% contribution around 144 amu, but in our mass spectra we could not find any dimer. Note, that we are comparing mass spectra of low-energy electron-impact and high-energy proton-impact, so that not all differences are due to cluster formation.…”

“…In an electron impact experiment with variable delays between ionization and ion extraction we previously found that the dissociation channels can be distinguished by the kinetic energy release (unpublished, paper in preparation). Kinetic energies of different mass peaks have been discussed by Ren [30] but competing dissociation channels hidden in one mass peak are not resolved in their work. From calculation of the standard enthalpy of formation, Collin attributes mass 42 to C 3 H + 6 [24], after Gallegos found C 2 H 2 O + to be more likely [23].…”