TY - JOUR
T1 - Negative ion formation through dissociative electron attachment to the group IV tetrabromides: Carbon tetrabromide, silicon tetrabromide and germanium tetrabromide
AU - Ómarsson, F. H.
AU - Reynisson, B.
AU - Brunger, M. J.
AU - Hoshino, M.
AU - Tanaka, H.
AU - Limão-Vieira, P.
AU - Ingólfsson, O.
N1 - This work was conducted under the support of the Icelandic Centre for Research (RANNIS), and the University of Iceland Research Fund. M.J.B. thanks the Australian Research Council for some financial support through the Centre for Antimatter-Matter Studies and H.T. and M.H. acknowledge the Japanese Ministry of Education, Sport, Culture and Technology. P.L.-V. acknowledges the PEst-OE/FIS/UI0068/2011 grant and his Visiting Professor position at Sophia University, Tokyo, Japan. F.H.O. acknowledges the Eimskip University Fund, for the award of a PhD grant. We also acknowledge the COST ACTION MP1002. Finally, the authors thank Ragnheidur Gudbrandsdottir and Benedikt Omarsson for running the calculations.
PY - 2014/5/15
Y1 - 2014/5/15
N2 - As a part of our efforts to characterize the electron attachment reactions of the group IV tetrahalides, XY4 (X = C, Si, Ge and Y = F, Cl, Br) we here follow up on our previous study on XF4 and report electron attachment to the tetrabromides: CBr4, SiBr4 and GeBr 4 in the incident electron energy range from about 0 to 10 eV. The formation of Br-, XBr3
-, XBr2
- and Br2
- is observed from all these compounds, and additionally the molecular anion is observed from SiBr 4. The main DEA contributions from CBr4 and GeBr 4 are observed through a low lying resonance, which we assign as a T2 shape resonance associated with a single occupation of the t 2 symmetry LUMO+1 of these molecules. This resonance is also apparent in the ion yield from SiBr4, but there the main contributions are the molecular anion and Br- in a narrow energy range peaking at 0 eV. We attribute these 0 eV contributions to a vibrational Feshbach resonance associated with the a1 symmetry LUMO. Further resonances are observed, for all the compounds investigated here, in the energy range between 3 and 6 eV. To establish the thermochemical thresholds for the individual channels we have conducted DFT calculations from which we report the threshold values, bond dissociation energies and electron affinities for individual fragments and their neutral precursors. These values are compared to values in the literature where available, and discussed in the context of our experimental results.
AB - As a part of our efforts to characterize the electron attachment reactions of the group IV tetrahalides, XY4 (X = C, Si, Ge and Y = F, Cl, Br) we here follow up on our previous study on XF4 and report electron attachment to the tetrabromides: CBr4, SiBr4 and GeBr 4 in the incident electron energy range from about 0 to 10 eV. The formation of Br-, XBr3
-, XBr2
- and Br2
- is observed from all these compounds, and additionally the molecular anion is observed from SiBr 4. The main DEA contributions from CBr4 and GeBr 4 are observed through a low lying resonance, which we assign as a T2 shape resonance associated with a single occupation of the t 2 symmetry LUMO+1 of these molecules. This resonance is also apparent in the ion yield from SiBr4, but there the main contributions are the molecular anion and Br- in a narrow energy range peaking at 0 eV. We attribute these 0 eV contributions to a vibrational Feshbach resonance associated with the a1 symmetry LUMO. Further resonances are observed, for all the compounds investigated here, in the energy range between 3 and 6 eV. To establish the thermochemical thresholds for the individual channels we have conducted DFT calculations from which we report the threshold values, bond dissociation energies and electron affinities for individual fragments and their neutral precursors. These values are compared to values in the literature where available, and discussed in the context of our experimental results.
KW - Bond dissociation energies
KW - Carbon tetrabromide
KW - Dissociative electron attachment
KW - Electron affinities
KW - Germanium tetrabromides
KW - Silicon tetrabromide
UR - http://www.scopus.com/inward/record.url?scp=84901953963&partnerID=8YFLogxK
U2 - 10.1016/j.ijms.2014.01.008
DO - 10.1016/j.ijms.2014.01.008
M3 - Article
AN - SCOPUS:84901953963
VL - 365-366
SP - 275
EP - 280
JO - International Journal of Mass Spectrometry
JF - International Journal of Mass Spectrometry
SN - 1387-3806
IS - SI
ER -