Bulletin of the American Physical Society
74th Annual Gaseous Electronics Conference
Volume 66, Number 7
Monday–Friday, October 4–8, 2021;
Virtual: GEC Platform
Time Zone: Central Daylight Time, USA
Session CT13: Collisions Involving Molecules
8:00 AM–10:00 AM,
Tuesday, October 5, 2021
Virtual Room: GEC platform
Chair: James Colgan, Los Alamos National Lab
Abstract: CT13.00004 : Identification of Siegert states in molecular scattering calculations and application to analysis of dissociative electron attachment*
8:45 AM–9:15 AM
In this talk I will describe a general method for localization and analysis of Siegert states in multi-electron molecules. The method is based on the R-matrix division of space  which enables a numerically stable and computationally efficient search for the exponentially diverging resonant and virtual states and the very diffuse weakly bound dipole-bound states. We show that all Siegert states in a selected part of the complex plane can be readily localized, including broad resonances. Finally, we study Siegert states as a function of geometry in electron collisions with a series of molecules (N2, HNCO, HCOOH, pyrrole). We identify near-threshold dipole-bound or virtual states as the source of the so-called ``σ* mechanism" in dissociative electron attachment to polar molecules.
 L.A. Morgan and P.G. Burke, J. Phys. B: At. Mol. Opt. Phys. 21, 2091 (1988).
*Support of the Czech Science Foundation as the project GA CR 20-15548Y and a support of Charles University as the project PRIMUS/20/SCI/003 is gratefully acknolwedged.
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