10.6084/m9.figshare.1012575.v1
Márcio T do N Varella
Márcio
T do N Varella
Sergio d'A Sanchez
Sergio d'A Sanchez
Márcio H F Bettega
Márcio H F Bettega
Marco A P Lima
Marco A P Lima
Luca Chiari
Luca Chiari
Antonio Zecca
Antonio Zecca
Emanuele Trainotti
Emanuele Trainotti
M J Brunger
M
J Brunger
Present theoretical elastic differential cross sections for positron collisions with iodomethane at selected energies
IOP Publishing
2013
iodomethane
ev
positron collisions
section
incident energy range
ch
3I
SMC approach
TCS data
ics
Atomic Physics
Molecular Physics
2013-08-19 00:00:00
Figure
https://iop.figshare.com/articles/figure/_Present_theoretical_elastic_differential_cross_sections_for_positron_collisions_with_iodomethane_at/1012575
<p><strong>Figure 2.</strong> Present theoretical elastic differential cross sections for positron collisions with iodomethane at selected energies. The results were obtained within the SMC approach, though employing Born dipole corrections for higher partial waves, see section <a href="http://iopscience.iop.org/0953-4075/46/17/175202/article#jpb474410s3" target="_blank">3</a>.</p> <p><strong>Abstract</strong></p> <p>We report experimental total cross sections (TCSs) and calculated elastic integral cross sections (ICSs) for positron collisions with iodomethane (methyl iodide, CH<sub>3</sub>I). The experimental TCSs were obtained with a linear transmission technique, for energies from 0.1 up to 50 eV. The present TCS data agree well with those previously reported (Kimura <em>et al</em> 2001 <em>J. Chem. Phys.</em> <strong>115</strong> 7442) at higher energies (above 7 eV), but significant discrepancies are found at the lower energies. The present ICS computations were performed with the Schwinger multichannel method (SMC) and the Born dipole approximation in the incident energy range from 0.1 eV up to 10 eV. Iodomethane poses a great challenge to theoretical descriptions of the collisions dynamics. In addition to the neglect of inelastic channels, the main difficulty found in the SMC approach is related to numerical limitations that prevent a thorough description of correlation–polarization effects. Although our ICS calculations do not compare well with the present TCS data, the results are encouraging, as iodomethane would challenge all the presently available computational approaches.</p>