Electron attachment to the 4-bromobiphenyl molecule and the decay channels of its molecular anion were investigated by means of Dissociative Electron Attachment (DEA) spectroscopy with two different spectrometers. The first apparatus is equipped with a static magnet mass analyzer (Ufa group) and the second one with a quadrupole mass filter (Prague group). The dominant DEA channel at low electron energy leads to formation of Br- negative fragments. Long-lived (τa = 40 µs at the temperature of 80 °C) molecular negative ions were detected only in the Ufa experiment. We explored the involved potential energy surfaces and found that the molecular anion has two distinct structures with the C-Br distances of 1.92 Å and 2.8 Å. The statistical model based on the Arrhenius approximation fully explains the experimental observations and sheds light on the earlier anion dissociation kinetic studies in solution.

Department of Dynamics of Molecules and Clusters J Heyrovský Institute of Physical Chemistry Academy of Sciences of the Czech Republic Dolejškova 3 18223 Prague 8 Czech Republic

Dipartimento di Chimica G Ciamician Università di Bologna Via Selmi 2 40126 Bologna Italy

Institute of Molecule and Crystal Physics UFRC RAS October Avenue 151 450075 Ufa Russia

Moscow Institute of Physics and Technology Institutskiy Pereulok 9 141700 Dolgoprudny Moscow Region Russia

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