We report partial cross sections for the dissociative electron attachment to pyruvic acid. A rich fragmentation dynamics is observed. Electronic structure calculations facilitate the identification of complex rearrangement reactions that occur during the dissociation. Furthermore, a number of fragment anions produced at electron energies close to 0 eV are observed, that cannot originate from single electron-molecule collisions. We ascribe their production to secondary reactions of the transient anions with neutral molecules. Such reactions turn out to be unusually efficient; the most probable reason for this is that they proceed via the formation of a double-hydrogen-bonded complex followed by an ultrafast proton transfer between the reaction partners.

We report cross-section results from experimental and theoretical studies on electron collisions with 1-butyne (HC≡C-CH 2 CH 3 ) and acetylene (HC≡CH) molecules and from computations for a propyne (HC≡C-CH 3 ) molecule. Absolute grand -total electron-scattering cross sections (TCSs) were measured at impact energies ranging from about 0.5 to 300 eV using the linear electron-transmission method. The TCS energy curve for 1-butyne has a very broad enhancement on which some distinct features are superimposed, namely a resonant-like maximum (located near 3.2 eV), a broad hump (centered around 7.5 eV), and a shoulder (spanned between 12 and 26 eV). The shape of our experimental TCS curve for acetylene closely resembles that reported earlier, while its magnitude is usually larger. As no previous calculations for electron collisions with 1-butyne and propyne are disclosed in the literature, we computed the elastic (ECS) and ionization (ICS) cross sections for these molecules. Similar calculations were also performed for acetylene molecules. The additivity rule was employed to calculate the ECSs from 50 to 3000 eV, while the binary-encounter-Bethe approach was used for computation of the ICSs, from the threshold up to 3000 eV. The sum (ECS + ICS) of these two computed cross sections reasonably reproduces the TCS measurements above 50 eV. Furthermore, the experimental TCS curves, obtained in our laboratory, for a series of acetylenic compounds-acetylene (HC≡CH), propyne (HC≡C-CH 3 ), and 1-butyne (HC≡C-CH 2 CH 3 )-are compared to study the substitutional effect. Finally, the influence of the structural differences on the electron-scattering TCS for isomers of the C 4 H 6 molecule (1-butyne, 2-butyne, and 1,3-butadiene) is indicated and discussed.

Fluoronitrile C3F7CN is a promising candidate for the replacement of SF6 dielectric gas in high-voltage insulation.