Low-energy electron scattering from methanol and ethanol

Abstract

Measured and calculated differential cross sections for elastic ͑rotationally unresolved͒ electron scattering from two primary alcohols, methanol ͑CH 3 OH͒ and ethanol ͑C 2 H 5 OH͒, are reported. The measurements are obtained using the relative flow method with helium as the standard gas and a thin aperture as the collimating target gas source. The relative flow method is applied without the restriction imposed by the relative flow pressure conditions on helium and the unknown gas. The experimental data were taken at incident electron energies of 1, 2, 5, 10, 15, 20, 30, 50, and 100 eV and for scattering angles of 5°-130°. There are no previous reports of experimental electron scattering differential cross sections for CH 3 OH and C 2 H 5 OH in the literature. The calculated differential cross sections are obtained using two different implementations of the Schwinger multichannel method, one that takes all electrons into account and is adapted for parallel computers, and another that uses pseudopotentials and considers only the valence electrons. Comparison between theory and experiment shows that theory is able to describe low-energy electron scattering from these polyatomic targets quite well.

Computation of electron-impact rotationally elastic total cross sections for methanol over an extensive range of impact energy (0.1 – 2000 eV)

“…Figures 3(a)-3(d) depict the behavior of DCSs as a function of angle theta (q) for incident energies 5, 10, 15, and 20 eV, respectively. We have compared the present DCS results with the experimental and theoretical results of Khakoo et al [7] for the incident energies 5, 10, 15, and 20 eV while the theoretical results of Lee et al [4] are reported for incident energies 5 and 10 eV. Khakoo et al [7] have used the Schwinger multichannel pseudopotential method (SWCPP) and the Schwinger multichannel all electron method (SMCAE) to compute DCSs.…”

“…We have compared the present DCS results with the experimental and theoretical results of Khakoo et al [7] for the incident energies 5, 10, 15, and 20 eV while the theoretical results of Lee et al [4] are reported for incident energies 5 and 10 eV. Khakoo et al [7] have used the Schwinger multichannel pseudopotential method (SWCPP) and the Schwinger multichannel all electron method (SMCAE) to compute DCSs. For energies below 10 eV, the Static Exchange Polarization (SEP) model is considered and above it only the Static Exchange (SE) model is used by them [7].…”

“…Khakoo et al [7] have used the Schwinger multichannel pseudopotential method (SWCPP) and the Schwinger multichannel all electron method (SMCAE) to compute DCSs. For energies below 10 eV, the Static Exchange Polarization (SEP) model is considered and above it only the Static Exchange (SE) model is used by them [7]. So no absorption effects are considered in the calculation.…”

“…Recent studies of electron interactions with methanol include the experimental studies of Lee et al [4] and Sugohara et al [5], who measured the elastic cross sections (ECSs) using a relative flow technique and reported cross sections in the range of 100-1000 eV. Silva et al [6] reported a total cross section (TCS) using the linear transmission method in the range of 60-500 eV while Khakoo et al [7] reported ECSs using a relative flow method for impact energies 1-100 eV. Szmytkowski and Krzysztofowicz [8] used the linear transmission method and measured TCSs in the * minaxivinod@yahoo.co.in range of 0.8-250 eV, and Sueoka et al [9] and Schmieder [10] measured TCSs in the range of 1-300 and 1.5-50 eV, respectively.…”

“…Khakoo et al [7] calculated ECSs using the Schwinger multichannel method in the range 1-100 eV. Ming and Hua [11] calculated TCSs using the additivity rule in the range of 10-1000 eV.…”