A comprehensive and comparative study of elastic electron scattering from OCS and CS2 in the energy region from 1.2 to 200 eV

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Differential, integral, and momentum transfer cross sections have been determined for the elastic scattering of electrons from the molecules CF3Cl, CF2Cl2, and CFCl3.With the help of a crossed electron beam–molecular beam apparatus using the relative flow technique, the ratios of the elastic differential cross sections (DCSs) of CF3Cl, CF2Cl2, and CFCl3 to those of He were measured in the energy region from 1.5 to 100 eV and at scattering angles in the range 15° to 130°. From those ratios, the absolute DCSs were determined by utilizing the known DCS of He. For CF3Cl and CF2Cl2, at the common energies of measurement, we find generally good agreement with the results from the independent experiments of Mann and Linder [J. Phys. B 25, 1621 (1992)10.1088/0953-4075/25/7/030; Mann and Linder J. Phys. B 25, 1633 (1992)10.1088/0953-4075/25/7/031]. In addition, as a result of progressively substituting a Cl-atom, undulations in the angular distributions have been found to vary in a largely systematic manner in going from CF4 to CF3Cl to CF2Cl2 to CFCl3 and to CCl4. These observed features suggest that the elastic scattering process is, in an independently additive manner, dominated by the atomic-Cl atoms of the molecules. The present independent atom method calculation typically supports the experimental evidence, within the screened additivity rule formulation, for each species and for energies greater than about 10–20 eV. Integral elastic and momentum transfer cross sections were also derived from the measured DCSs, and are compared to the other available theoretical and experimental results. The elastic integral cross sections are also evaluated as a part of their contribution to the total cross section.

Section: Theoretical Outlinecontrasting

confidence: 52%

Section: Theoretical Outlinementioning

confidence: 99%

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Cross sections for elastic scattering of electrons by CF3Cl, CF2Cl2, and CFCl3

Hoshino

Horie

Kato

et al. 2013

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“…22,23 In a recent work on the elastic scattering from the halomethane-molecules, CH 3 F, CH 3 Cl, CH 3 Br, and CH 3 I, 24 we have shown for the first time atomic-like behavior of these scattering systems by comparing the elastic DCSs of these molecules with those for the corresponding noble gases, Ne, Ar, Kr, and Xe, respectively. Such behavior was soon after shown for other molecular systems as CCl 4 , 25 SiF 4 , 26 GeF 4 , 27 COS and CS 2 , 28 and C 4 F 6 isomers 29 scattering systems by comparison of the elastic DCSs for corresponding atomic chlorine, fluorine, and sulphur atoms in the intermediate impact energy region, respectively. Here, we also verify, for the first time, such atomic-like behavior in the electron scattering processes from XF 3 (X = B, C, N, and CH) molecules.…”

Section: Introductionmentioning

confidence: 99%

Crossed-beam experiment for the scattering of low- and intermediate-energy electrons from BF3: A comparative study with XF3 (X = C, N, and CH) molecules

Hoshino

Limão‐Vieira

Suga

et al. 2015

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Absolute differential cross sections (DCSs) for electron interaction with BF 3 molecules have been measured in the impact energy range of 1.5-200 eV and recorded over a scattering angle range of 15 • -150 • . These angular distributions have been normalized by reference to the elastic DCSs of the He atom and integrated by employing a modified phase shift analysis procedure to generate integral cross sections (ICSs) and momentum transfer cross sections (MTCSs). The calculations of DCSs and ICSs have been carried out using an independent atom model under the screening corrected additivity rule (IAM-SCAR). The present elastic DCSs have been found to agree well with the results of IAM-SCAR calculation above 20 eV, and also with a recent Schwinger multichannel calculation below 30 eV. Furthermore, in the comparison with the XF 3 (X = B, C, N, and CH) molecules, the elastic DCSs reveal a similar angular distribution which are approximately equal in magnitude from 30 to 200 eV. This feature suggests that the elastic scattering is dominated virtually by the 3-outer fluorine atoms surrounding the XF 3 molecules. The vibrational DCSs have also been obtained in the energy range of 1.5-15 eV and vibrational analysis based on the angular correlation theory has been carried out to explain the nature of the shape resonances. Limited experiments on vibrational inelastic scattering confirmed the existence of a shape resonance with a peak at 3.8 eV, which is also observed in the vibrational ICS. Finally, the estimated elastic ICSs, MTCSs, as well as total cross sections are compared with the previous cross section data available. C 2015 AIP Publishing LLC. [http://dx

“…[38][39][40][41][42] Briefly, each atomic target (C, Cl, H) is represented by an interacting complex potential, the so-called optical potential. The real part accounts for the elastic scattering of the incident electrons, and the imaginary part represents the inelastic processes, which is considered as "absorption" from the incident beam.…”

Section: B Independent Atom Model Calculationsmentioning

confidence: 99%

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

Barbosa

Varella

Sanchez

et al. 2016

Absolute cross sections for electronic excitation of pyrimidine by electron impact J. Chem. Phys. 144, 024302 (2016) In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7 • to 110 • . From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene. Published by AIP Publishing. [http://dx