Transferability of local-density norm-conserving pseudopotentials to electron-molecule-collision calculations

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

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“…28 The method was recently reviewed 29 and here we will provide only the relevant points for the present calculations.…”

Section: A the Schwinger Multichannel Methods Implemented With Pseudomentioning

confidence: 99%

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

Barbosa

Varella

Sanchez

et al. 2016

The Journal of Chemical Physics

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“…The Schwinger multichanel (SMC) method [9][10][11] and its implementation with pseudopotentials [12] have been described in detail in several publications. We will only discuss the points relevant for the present calculations.…”

Section: Theorymentioning

confidence: 99%

Electron collisons with cyclobutane

Bettega¹,

Lopes²,

Lima³

et al. 2006

Braz. J. Phys.

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We report integral, differential, and momentum transfer cross sections for elastic scattering of low-energy electrons by cyclobutane (c-C 4 H 8 ), which is an isomer of the C 4 H 8 molecule and has a closed chain. Our calculations were performed with the Schwinger multichannel method with pseudopotentials at the static-exchange level of approximation, for energies up to 50 eV. We compare the cross sections of cyclobutane with the cross sections of other three isomers of C 4 H 8 , namely, isobutene, cis-2-butene, and skew-1-butene. These isomers have open chain and were the subject of a previous study by our group [Lopes et al. J. Phys. B 37, 997 (2004)]. We also show previous calculated integral and momentum transfer cross sections for isomers of C 3 H 4 , C 3 H 6 and C 4 H 6 , which have open and closed chains. For each isomeric group we discuss the isomer effect focusing on the closed chain isomer. The isomer effect is related to differences in the isomers cross sections due to differences in their geometries.

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“…Even at the lowest level of approximation, the static-exchange ͑SE͒ approximation, in which only direct ͑Coulomb͒ and exchange interactions between the incident electron and the molecule are considered, the computational demands grow severe for larger molecules. Pseudopotentials have proven effective in dealing with molecules containing heavier atoms, 13 both within the static-exchange approximation 14 and also in more complex calculations that include simultaneously multichannel coupling and polarization effects. 15 Massively parallel computers have also been used with success to obtain elastic and inelastic cross sections for scattering of electrons by large molecules.…”

Section: Introductionmentioning

confidence: 99%

Elastic scattering of low-energy electrons by benzene

Bettega

Winstead

McKoy

2000

The Journal of Chemical Physics

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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.

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Transferability of local-density norm-conserving pseudopotentials to electron-molecule-collision calculations

Cited by 208 publications

References 33 publications

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

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

Electron collisons with cyclobutane

Elastic scattering of low-energy electrons by benzene

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