Electronimpact electronic excitation of molecular nitrogen using the Schwinger multichannel variational method
Abstract
The Schwinger multichannel method is applied to study the lowenergy electronimpact excitation of molecular nitrogen. The scattering amplitudes are obtained within the minimal orbital basis for single configuration interactions (MOBSCI) level of approximation, for impact energies from near threshold up to 30 eV. Through the use of the MOBSCI strategy we have performed a closecoupling calculation for up to nine states, including the ground state and all singlet and triplet states resulting from the {pi}{sub u}{yields}{pi}{sub g} transitions. Integral and differential cross sections for the X {sup 1}{sigma}{sub g}{sup +}{yields}A {sup 3}{sigma}{sub u}{sup +}, W {sup 3}{delta}{sub u}, B{sup '} {sup 3}{sigma}{sub u}{sup }, a{sup '} {sup 1}{sigma}{sub u}{sup }, and w {sup 1}{delta}{sub u} electronic transitions are presented and compared with available experimental data and also with other theoretical results.
 Authors:
 Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Caixa Postal 6165, 13083970 Campinas, Sao Paulo (Brazil)
 Publication Date:
 OSTI Identifier:
 20982119
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.75.022705; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 74 ATOMIC AND MOLECULAR PHYSICS; APPROXIMATIONS; CONFIGURATION INTERACTION; COUPLING; DIFFERENTIAL CROSS SECTIONS; ELECTRONMOLECULE COLLISIONS; ELECTRONS; EV RANGE; EXCITATION; GROUND STATES; NITROGEN; SCATTERING AMPLITUDES; TRIPLETS; VARIATIONAL METHODS
Citation Formats
Da Costa, Romarly F., and Lima, Marco A. P. Electronimpact electronic excitation of molecular nitrogen using the Schwinger multichannel variational method. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVA.75.022705.
Da Costa, Romarly F., & Lima, Marco A. P. Electronimpact electronic excitation of molecular nitrogen using the Schwinger multichannel variational method. United States. doi:10.1103/PHYSREVA.75.022705.
Da Costa, Romarly F., and Lima, Marco A. P. Thu .
"Electronimpact electronic excitation of molecular nitrogen using the Schwinger multichannel variational method". United States.
doi:10.1103/PHYSREVA.75.022705.
@article{osti_20982119,
title = {Electronimpact electronic excitation of molecular nitrogen using the Schwinger multichannel variational method},
author = {Da Costa, Romarly F. and Lima, Marco A. P.},
abstractNote = {The Schwinger multichannel method is applied to study the lowenergy electronimpact excitation of molecular nitrogen. The scattering amplitudes are obtained within the minimal orbital basis for single configuration interactions (MOBSCI) level of approximation, for impact energies from near threshold up to 30 eV. Through the use of the MOBSCI strategy we have performed a closecoupling calculation for up to nine states, including the ground state and all singlet and triplet states resulting from the {pi}{sub u}{yields}{pi}{sub g} transitions. Integral and differential cross sections for the X {sup 1}{sigma}{sub g}{sup +}{yields}A {sup 3}{sigma}{sub u}{sup +}, W {sup 3}{delta}{sub u}, B{sup '} {sup 3}{sigma}{sub u}{sup }, a{sup '} {sup 1}{sigma}{sub u}{sup }, and w {sup 1}{delta}{sub u} electronic transitions are presented and compared with available experimental data and also with other theoretical results.},
doi = {10.1103/PHYSREVA.75.022705},
journal = {Physical Review. A},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}

As a first application of the Schwinger multichannel theory, we have calculated integral and differential cross sections for electronimpact excitation of the transition X /sup 1/..sigma../sub g//sup +/..>..b /sup 3/..sigma../sub u//sup +/ in H/sub 2/ for scattering energies from 13 to 30 eV at the twostate level. We find good agreement between our integral cross sections and the results obtained previously in a twostate closecoupling study. Our method does not rely on singlecenter expansions to calculate the bodyframe scattering amplitude and is designed to be applicable to molecules of arbitrary geometry.

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The complex Kohn variational method is employed in fourstate closecoupling calculations to generate integral and differential cross sections for lowenergy electronimpact excitation of the {sup 1}{Sigma}{sub g}{sup +}{r arrow}(b {sup 3}{Sigma}{sub u}{sup +}, {sup 3}{Sigma}{sub g}{sup +}, and {ital c} {sup 3}{Pi}{sub {ital u}}) transitions in H{sub 2}. The integral cross sections for excitation of the {sup 3}{Sigma}{sub g}{sup +} and {ital c} {sup 3}{Pi}{sub {ital u}} states from the ground state are found to be significantly different from earlier twostate calculations. The {ital a} {sup 3}{Sigma}{sub {ital g}}{sup +} cross sections are also larger than the most recent experimentalmore » 
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We report integral and differential cross sections for the electronimpact excitation of the {ital b} {sup 3}{Sigma}{sup +} state of CO using the Schwinger multichannel formulation. The calculations were carried out using a twostate approximation, with the incident electron energies in the range from 10.66 to 20 eV. We find four peaks in the inelastic cross section, centered at approximately 10.87, 11.6, 13.4, and 16.2 eV. The origins of the peak structures are discussed in terms of a partialwave analysis, and comparison is made with experiment and theory where appropriate. We attribute the two sharp, lowenergy (10.87 and 11.6 eV)more » 
Positronium formation using the multichannel Schwinger variational principle
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