Very low energy electron scattering by O₂

Abstract

We have performed high resolution electron beam transmission experiments in 0, over the energy range 12 meV to I eV. We estimate an approximate trend in widths of the d = 4 , 5 and 6 resonance states of the 0; intermediate and again the approximate trend in the relative contributions ofthe I =2,4 and 6 partial waves. Widths lie in the meV range as found previously for U'= 6 by Field et 01 and higher partial waves contribute less at lower energies. Analysis ofthe non-resonant elastic scattering data below 100 meV shows that scattering takes place through an interaction dominated by s-waves.

The Only Stable State of O2-Is the X2ΠgGround State and It (Still!) Has an Adiabatic Electron Detachment Energy of 0.45 eV

“…Here, we present vibrational and spin−orbit state-resolved ultraviolet photoelectron spectra and high-level ab initio quantum mechanical calculations that show unequivocally that these assignments 41-43 of a high electron affinity and of multiple adiabatically electronically bound O 2 - excited states are incorrect. Our results may be compared with previous photoelectron spectroscopy 11-20 and electron scattering ,,− ,− experiments and theoretical calculations. ,− …”

Rydberg electron transfer to C60 and C70

“…We also note, that the data of Jaffke et al [20] -which were obtained with a magnetically confined electron beam and therefore are expected to access the lowest energies more easily (see, e.g. [32]) -do not provide evidence for an attachment threshold at energies above zero, neither for C nor for C . In order to investigate this aspect for C\ in more detail, we inspected the threshold regions of the original data for SF\ and C\ [20] with the aim to provide estimates for analytical expressions of the cross section of C\ formation which would reproduce the measured data (see appendix for details).…”

Resonance and Threshold Phenomena in Low-Energy Electron Collisions with Molecules and Clusters

“…In Fig. 14 we show an apparatus (Hoffmann et al, 2002) which has been used in this or similar form by Field and Ziesel with coworkers (Field et al, 1991a;Ziesel et al, 1993;Gulley et al, 1998a, b;Field et al, 2000;Lunt et al, 2001;Field et al, 2001a, b, c;Jones et al, 2002;Ziesel et al, 2003) to investigate total electron scattering cross-sections for a large number of molecules from low (about 20 meV) to medium electron energies (around 10 eV). Electrons are created in the source region by photoionization of ground state argon atoms (at a pressure of a few tens of mPa) through the narrow Ar(11s 0 , J ¼ 1) resonance at 78.65 nm (about 4 meV above the photoionization threshold), using focussed (10-20 mm) monochromatized synchrotron radiation.…”