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Absorption effects in intermediate energy electron scattering by n-butane (C4H10)
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2012 J. Phys.: Conf. Ser. 388 052026
(http://iopscience.iop.org/1742-6596/388/5/052026)
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XXVII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2011) IOP Publishing
Journal of Physics: Conference Series 388 (2012) 052026
doi:10.1088/1742-6596/388/5/052026
Absorption effects in intermediate energy electron scattering by n–butane
(C4H10)
G. L. C. Souza*1, M.-T. Lee† 2, L. E. Machado†, A. S. Santos†, L. M. Brescansin** and R. R. Lucchese††
*
Instituto de Ciências Exatas e Tecnologia, UFAM, Itacoatiara, AM, 69100-000, Brazil
†
Departamento de Física, UFSCar, São Carlos, SP, 13565-905, Brazil
**
Instituto de Física “Gleb Wataghin”, UNICAMP, Campinas, SP, 13083-970, Brazil
††
Department of Chemistry, Texas A&M University, College Station, TX, 77840, USA
Synopsis This work presents a theoretical study on electron collisions with butane in the intermediate energy range. Results
obtained with and without including absorption effects are presented.
Although several solid-based ab-initio theoretical methods have been developed in the past
few decades for the investigation on electronmolecule collisions, most of them can only be
successfully applied in the low incident electron
energy range. At intermediate-energies, numerous open inelastic scattering channels are responsible for absorption effects that play important roles on the collision dynamics. Very recently, our group has introduced a modification
[1] in model absorption potential of Staszewska
et al [2] which has been successfully applied for
electron scattering by several atomic and small
molecular targets.
In this work, we apply this model potential to
a medium size polyatomic molecule, namely nbutane. A complex optical potential, given by:
Vopt  V st  Vex  Vcp  iVab
References
is used to represent the e--C4H10 interaction dynamics. In the above equation, Vst and Vex are
the static and the exchange components respectively. Vcp is the correlation-polarization contribution obtained in the framework of the freeelectron-gas model [3], and Vab is the improved
model absorption potential developed by our
group [1].
The scattering equation with this optical potential is solved iteratively using the Padé´s approximant method, as described by Gianturco et
al. [4].
In Figure 1 we show our calculated differential cross sections (DCS) for elastic e--C4H10 at
50eV, obtained with and without the inclusion
of absorption effects, along with some selected
experimental results. Additional results will be
presented at the Conference.
This work was partially supported by the
Brazilian agency CNPq.
1
2
E-mail: [email protected]
E-mail: [email protected]
Published under licence by IOP Publishing Ltd
Figure 1. DCS for elastic electron scattering by
C4H10 at 50eV. Solid line, present results including
absorption effects; dashed line present results without including absorption; full circles, experimental
results of Sanches et al [5].
1
[1] M.-T. Lee et al 2007 J. Electron Spectrosc. Rel.
Phenom. 155 14
[2] G. Staszewska et al 1983 Phys. Rev. A 28 2740
[3] N. T. Padial and D. W. Norcross 1983 Phys. Rev. A
28 697
[4] F. A. Gianturco, R. R. Lucchese and N. Sanna 1995
J. Chem. Phys. 102 5743
[5] I. P. Sanches et al 2008 J. Phys. B 41 185202