Acetylene, 12C2H2: Refined analysis of CRDS spectra around 1.52 μm

The analysis of CW-cavity ring down absorption spectra of (C2H2)-C-12 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 (C2H2)-C-12 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 (CHCH)-C-12-C-13 present in natural abundance in the gas sample were also assigned. (C) 2011 Elsevier Inc. All rights reserved.