Electron excitation of the Schumann–Runge continuum, longest band, and second band electronic states in O2

Abstract

We report measurements of differential and integral cross sections for electron excitation of the Schumann–Runge continuum, longest band, and second band electronic states in molecular oxygen. The energy range of the present study is 15–200 eV, with the angular range of the differential cross section (DCS) measurements from 2 to 130°. A generalized oscillator strength analysis is then employed in order to derive integral cross sections (ICSs) from the corresponding DCSs, and these ICSs are compared with relevant energy and oscillator strength scaled Born cross section (BEf-scaling [Y.-K. Kim, J. Chem. Phys. 126, 064305 (2007)]) results determined as a part of this investigation. Interestingly, while the present Schumann–Runge continuum and second band ICSs were in reasonable agreement with the respective BEf-scaling results, agreement for the longest band was poor below 100 eV with a possible reason for this apparently anomalous behavior being canvassed here. Finally, where possible all present data are compared with the results from earlier measurements and calculations with the level of agreement found being very good in some cases and marginal in others.

A study of electron scattering from benzene: Excitation of the 1B1u, 3E2g, and 1E1u electronic states

“…Thus, the level of agreement seen in Fig. 5 is heartening, and consistent with what we have observed previously 46,[56][57][58][59][60][61] for other species when resonance (i.e., the decay of a temporary negative (anion) state into the channel in question) effects are not apparent and when strong Rydberg-valence interactions are absent. With respect to Fig.…”

“…5, we find a truly remarkable level of accord between our experimental ICSs and those from the BE f-scaling technique, over the common energy range of comparison. Benzene is by far the largest molecule we have yet considered in our studies 46,[56][57][58][59][60][61] seeking to investigate the efficacy of the BE fscaling approach, in particular in relation to providing reliable data bases for the plasma modeling community. Thus, the level of agreement seen in Fig.…”

Electronic excitation of carbonyl sulphide (COS) by high-resolution vacuum ultraviolet photoabsorption and electron-impact spectroscopy in the energy region from 4 to 11 eV

“…However, as observed in the high-resolution photoabsorption spectrum, the 1 Σ + state is overlapped with other vibrational progression as well as with the Rydberg-valence state of sσ with which the BE f -scaling approach may has its own limits of applicability, as is found in the longest band of O 2 . 39 Furthermore, the contribution of strong Rydberg-valence mixing affecting the 1 Π state may certainly be a general limitation in the BE f -scaling approach. These verifications await further investigations, both experimental and theoretical in the intermediate energy region below 60 eV.…”

Transport coefficients and cross sections for electrons in water vapour: Comparison of cross section sets using an improved Boltzmann equation solution

“…Nonetheless, we caution that the Born approximation is not a very sophisticated approach and that as a result of this scaling procedures are often employed in conjunction with its use. 33,34 …”