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First observation of the 3Πg3 state of C2: Born-Oppenheimer breakdown

Authors :
O. Krechkivska
Timothy W. Schmidt
Klaas Nauta
George B. Bacskay
Scott H. Kable
B. A. Welsh
Source :
The Journal of Chemical Physics. 146:134306
Publication Year :
2017
Publisher :
AIP Publishing, 2017.

Abstract

The 33Πg state of the dicarbon molecule, C2, has been identified for the first time by a combination of resonant ionization spectroscopy, mass spectrometry, and high-level ab initio quantum chemical calculations. This marks the discovery of the final valence triplet state of C2 spectroscopically accessible from the lowest triplet state. It is found to be vibronically coupled to the recently discovered 43Πg state, necessitating vibronic calculations beyond the Born-Oppenheimer approximation to reconcile calculated rotational constants with observations. The 33Πg state of C2 is observed to have a much shorter fluorescence lifetime than expected, possibly pointing to predissociation by coupling to the unbound d3Πg state.

Details

ISSN :
10897690 and 00219606
Volume :
146
Database :
OpenAIRE
Journal :
The Journal of Chemical Physics
Accession number :
edsair.doi...........b8413c63cdf263236d528790427f9898