Communication: On the first ionization threshold of the C 2 H radical

B. Gans (1) , G. Garcia (2) , F. Holzmeier (3) , J. Krüger (2) , A. Röder (3) , A. Lopes (4) , C. Fittschen (5) , J. Loison (6) , C. Alcaraz (4)

1 ISMO - Institut des Sciences Moléculaires d'Orsay
2 SSOLEIL - Synchrotron SOLEIL
3 IPTC - Institut of Physical and Theoretical Chemistry [Würzburg]
4 LCPO - Laboratoire de Chimie Physique D'Orsay
5 PC2A - Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522
6 ISM - Institut des Sciences Moléculaires

The slow photoelectron spectrum of the ethynyl radical has been recorded for the first time by using the DESIRS beamline of the SOLEIL synchrotron facility. Ethynyl was generated using a microwave discharge flow tube. The observation of the X+Π3←XΣ+2 transition allowed the first direct measurement of the adiabatic ionization threshold of this radical (EI = 11.641(5) eV). The experimental results are supported by ab initio calculations. Our preliminary investigation of the cationic ground state potential energy surfaces predicts a non-negligible Renner-Teller effect which has not been discussed previously.

Domaines: Physique [physics]

B. Gans, G. Garcia, F. Holzmeier, J. Krüger, A. Röder, et al.. Communication: On the first ionization threshold of the C 2 H radical. Journal of Chemical Physics, 2017, 146 (1), pp.011101. ⟨10.1063/1.4973383⟩. ⟨hal-02072221⟩