Elastic scattering of low-energy electrons by benzene

Abstract

We present elastic cross sections obtained from ab initio calculations for low-energy electron scattering by benzene, C 6 H 6 . The calculations employed the Schwinger multichannel method as implemented for parallel computers within both the static-exchange and staticexchange-polarization approximations. We compare our results with other theoretical calculations and with available experimental data. In general, agreement is good.

Resonant Channel Coupling in Electron Scattering by Pyrazine

“…This was an unexpected result, because the most critical issue in obtaining good resonance energies is accounting for target polarization, which one might expect to be less important for R 3 than for R 1 and R 2 due to the decreased target-projectile interaction time. The same pattern was found in earlier calculations on benzene [16,17] and the two-ring (purine) nucleobases adenine and guanine [18]; although we noted [17,18] the possible influence of coupling to core-excited resonances, we did not then explore it.Here we investigate the observed trend in -ring resonance energies by studying the diazabenzene molecule pyrazine (Fig. 1).…”

“…The failure of previous calculations [12,13,17] to allow for excitation to low-lying triplet states thus accounts for much of the disagreement seen between the results of those calculations and related measurements [8,14,15]. Obviously, future calculations using all-electron methods should take the triplet states into account, either by including appropriate closed-channel terms in an SEP wave function, as was done here, or, perhaps better still, by explicitly including the lowest triplet states as open channels above their respective thresholds.…”

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

“…Finally, we note the total ionization cross section results from measurements due to Schram et al 29 From a theoretical perspective, elastic electron scattering from C 6 H 6 , at energies up to about 40 eV, using single-center expansion methods at the static exchange level, were reported by Gianturco and Lucchese. 30 Elastic data were also reported by Bettega et al, 31 although in this case the Schwinger multichannel method at both the static exchange and static exchange plus polarization levels was utilized. Ma et al, 32 using an independent atom model approach, reported elastic differential cross sections (DCSs), integral cross sections (ICSs) and momentum transfer cross sections for e − -C 6 H 6 scattering in the 100-1000 eV range.…”

Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

“…10 There are at least two previous works available in the literature reporting cross sections for low-energy electron scattering by benzene. 50,51 Especially, we highlight the ab initio calculation performed by Bettega et al, 50 also using the SMC method, which placed the π * resonances at 2.23 eV and 8.39 eV, with the first resonance being double degenerate. In this work, we see that the breakage of symmetry due to the chlorine atom "splits" the first resonance of benzene into two, as expected, even though the experimental data are unable to observe this.…”