Cavity ring-down spectroscopy of acetylene near 0.8μm

A continuous-wave cavity ring-down spectrometer was employed to record the spectrum of the acetylene molecule spanning the 12350 - 12790 cm⁻¹ region. A total of 747 lines from the principal isotopologue and 68 lines from ¹²C¹³CH${}_2$ were identified, with nearly all line intensities retrieved from the spectra. These lines belong to eighteen vibrational bands of ¹²C${}_2$H${}_2$ and two vibrational bands of ¹²C¹³CH${}_2$, among which five vibrational bands are reported here for the first time. Spectroscopic constants were deduced for all the identified bands, and the vibrational dipole moment squared along with Herman–Wallis coefficients were determined for the majority of these bands. Additionally, several resonance interactions were thoroughly explored.