The absorption spectrum of acetylene by CRDS between 7244 and 7918 cm−1

- High sensitivity spectra of 12C2H2 were recorded by Cavity Ring Down Spectroscopy.
- The CRDS spectra were analyzed between 7244 and 7918 cm−1.
- Predictions of the global effective Hamiltonian were used to assign the spectrum.
- Two thousand one hundred and three lines were rovibrationally assigned to 34 bands, 26 bands being newly observed.
- The reported data will be valuable to refine the global 12C2H2 effective Hamiltonian.

The absorption spectrum of acetylene has been recorded using high sensitivity cavity ring down spectroscopy (αmin~5×10−11 cm−1) in the 7244-7918 cm−1 interval corresponding to a weak absorption region. The CRDS spectra revealed new bands which were identified on the basis of a global effective Hamiltonian model (Lyulin OM, Perevalov VI, Teffo JL. Proc. SPIE 2004;5311:134-43). Overall, about 2100 lines were rovibrationally assigned in the investigated interval. They belong to 26 new bands and to the eight already known bands of the region, for which additional J-lines were assigned. The spectroscopic parameters were derived from a band by band fit of the line positions. Part of the analyzed bands was found affected by strong rovibrational perturbations which are discussed. These new data will be valuable to refine the global effective Hamiltonian of 12C2H2 at higher energy.