Electron collisions with ethylene

Abstract

We have measured absolute elastic scattering and vibrational excitation cross sections for electron impact on ethylene. The experimental data have been obtained on two different crossed-beam electron spectrometers and they cover the energy range from 1 to 100 eV and scattering angles between 10° and 130°. Both differential (in angle) and energy-dependent cross sections have been measured. The differential cross sections have also been analysed using a molecular phase shift analysis technique in order to derive the integral elastic and elastic momentum transfer cross sections. Comparison is made with earlier data, where available, and also with a number of recent theoretical calculations.

Electron impact excitation of the ã 3B1u electronic state in C2H4: An experimentally benchmarked system?

“…(1) that the product R(E 0 , θ ) × σ 0 (E 0 , θ ) then gives the required ã 3 B 1u DCS provided σ 0 (E 0 , θ ) is known. In the present study our preferred elastic ethylene differential cross sections are those obtained by Panajotovic et al, 58 although we note that their results are largely consistent with those from the independent studies of Khakoo et al 59 and Allan et al 38 Hence, we are confident in their 58 validity. Equation (1) is only valid if the transmission efficiency of the analyser remains constant over the energy loss and the angular range studied, or is at least well characterised.…”

Recent advances in the application of the Schwinger multichannel method with pseudopotentials to electron-molecule collisions

“…The use of the fictitious thresholds, therefore, represents a very promising strategy that will be further explored in future applications of the SM-CPP method for studying electron-molecule collisions. [138] obtained up to a 45ch-sep level of approximation; dashed (red) line, theoretical results from reference [138] obtained at the 1ch-sep level of approximation; solid (brown) line, theoretical results obtained up to a 45ch-sep with fictitious thresholds level of approximation from reference [138]; circles, diamonds, squares and stars, experimental data from references [143][144][145][146], respectively.…”

Analytically continued Fock space multi-reference coupled-cluster theory: Application to the shape resonance

“…In particular, the observation of the 2 B 2g state of ethylene anion by electron transmission spectroscopy shows that the resonance is centered near 1.78 eV with a width of approximately 0.7 eV [30]. The vibrational excitation studies of Walker et al [40] and the absolute elastic scattering and vibrational excitation cross-sections experiments done by Panajotovic et al [41] confirm these findings. Although significant vibrational excitation occurs, the vibronic width in each channel is approximately constant.…”

“…Although significant vibrational excitation occurs, the vibronic width in each channel is approximately constant. The electron transmission spectrum of ethylene [41] shows exceedingly weak vibrational substructure. Thus, a single calculation of a resonance width has meaning within the usual fixed nucleus approximation used in this study.…”

“…2 B 2g shape resonance in C 2 H À 4 It is known that isolated C 2 H 4 (ethylene) anion is not electronically stable [31]. There are several experimental [40,41] and theoretical [42][43][44] reports available in the literature that describe the position and lifetime of the Table 1 Energy and width of the 2 P shape resonance in e À -Mg scattering low-energy (p) 2 (p * ) 1 ( 2 B 2g ) shape resonance of ethylene anion. In particular, the observation of the 2 B 2g state of ethylene anion by electron transmission spectroscopy shows that the resonance is centered near 1.78 eV with a width of approximately 0.7 eV [30].…”