Low-Energy Electron Capture by 6-Aza-2-thiothymine: Investigations by Electron Attachment and Electron Transmission Spectroscopies

Authors

Stanislav A. Pshenichnyuk, Russian Academy of SciencesFollow
Gordon A. Gallup, University of Nebraska - LincolnFollow
Paul Burrow, University of Nebraska - LincolnFollow

Date of this Version

2007

Citation

Published in Journal of Physical Chemistry A 111 (2007), pp 11837-11842

doi:10.1021/jp076765b

Comments

Copyright © 2007 American Chemical Society. Used by permission.

Abstract

The interaction of low-energy (0-10 eV) electrons with 6-aza-2-thiothymine is investigated in the gas phase by studies of sharp structure in the total electron scattering cross section and by mass analysis of the stable or long-lived negative ions produced by electron attachment. The most efficient fragmentation process, occurring at 0.15 eV, involves the ejection of a closed-shell neutral molecule (CH₃CN). Ab initio calculations support our proposal that this process leads to ring closure to form a stable four-member heterocyclic anion. A long-lived parent anion with an approximate lifetime of 75 microseconds is observed near zero electron energy, and evidence is also seen for the slow decay of this anion by ejection of CH₃CN. Near 3.3 eV, an anion of m/e 41 is produced that is likely to be a metastable valence anion of bent CH₃CN, but the dipole-bound anion cannot be ruled out.