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Experimental Evidence on the Mechanism of Dissociative Electron Attachment to Formic Acid

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Publication date 2013
Author Janečková Radmila, Kubala Dušan, May Olivier, Fedor Juraj, Allan Michael,
Project Chemical and Physical Processes from Electron-Molecule Interactions
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Original article (peer-reviewed)

Journal Physical Review Letters
Volume (Issue) 111
Page(s) 213201
Title of proceedings Physical Review Letters
DOI 10.1103/PhysRevLett.111.213201

Open Access


Two mechanisms for dissociative electron attachment in HCOOH, the formation of HCOO- + H, were proposed in the literature: (i) via a direct electron attachment into a sigma* resonance, augmented by dipole binding of the incident electron [G. A. Gallup et al., Phys. Rev. A 79, 042701 (2009)], and (ii) with the 1.8 eV resonance as a doorway state, linked to the products by symmetry lowering–distortion of the temporary anion, primarily the C—H bond, from the planar symmetry [T.N. Rescigno et al., Phys. Rev. Lett. 96, 213201 (2006)]. The later mechanism implies a reduction of the cross section upon deuteration of the hydrogen bonded to the C atom, whereas the former mechanism would leave the cross section unaffected. Our experimental absolute cross sections for the four isotopomers of formic acid show that deuteration on the C atom reduces the cross section value only marginally (by 12%) compared to deuteration on the O atom (reduction by a factor of 16), and thus favor mechanism (i).