Acetylene, 12C 2H 2: Refined analysis of CRDS spectra around 1.52 μm

• Published in: Journal of molecular spectroscopy 2011-05, Vol.267 (1), p.80-91
• Main Authors: Amyay, B., Herman, M., Fayt, A., Campargue, A., Kassi, S.
• Format: Article
• Language: English
• Subjects: Acetylene; CRDS; Global analysis; Interpolyad coupling; Optics; Overtone spectroscopy; Physics; Polyads
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1016/j.jms.2011.02.015

Selected set of interaction schemes in normal acetylene, within two polyads with k even and odd, and of Coriolis nature between these two polyads. [Display omitted] ► New assignments in CRDS spectra of 12C 2H 2 around 1.52 μm. ► Successful global analysis of 18 415 lines, including Coriolis coupling. ► Evidence for local interpolyad coupling. The analysis of CW-cavity ring down absorption spectra of 12C 2H 2 previously reported by Robert et al. (Mol. Phys. 106 (2008) 2581) was improved in the range 6667–7015 cm −1. Some 1825 lines were newly assigned. They either belong to 105 new sub-bands, involving 69 previously unreported sub-states, or extend assignments in 35 already known sub-bands. A global fit procedure of line positions from the full 12C 2H 2 database containing 18 415 lines, including those newly assigned, was performed, accessing vibrational states up to 8900 cm −1. Coriolis interactions were systematically introduced in the global Hamiltonian, which also accounted for higher order vibrational constants and considered the role of higher excited bending states than before. The dimensionless standard deviation of the fit was 1.07 and 396 effective vibration–rotation parameters were determined. Two local, interpolyad couplings were evidenced for the first time. A set of 121 new lines from 12CH 13CH present in natural abundance in the gas sample were also assigned.