The 2ν9 Band of Propyne-d3

High-resolution Fourier transform spectra of CD3CCH at room temperature and at 195 K have been recorded in the region of the 2ν9 band (1225-1285 cm−1) at an apodized resolution of 0.004 cm−1. Approximately 1000 vibration-rotation transitions in the P and R branches of 2ν9 (A1) have been fitted with a standard deviation of 0.00035 cm−1. Two vibration-rotation interactions, a Fermi resonance with (ν9 + 2ν10)±3 (A1), and a weak xy-Coriolis interaction with (ν9 + 2ν10)±1 (E), have been identified and analyzed. The parameters of the 2ν9 (A1) state and some of the those of the interacting states have been determined.