The infrared spectrum of the 2ν9, ν9+ν10, 2ν10 band system in allene-d4

The effects of first order Coriolis interactions and vibrational l type resonances in the infrared spectrum of the band system 2ν9 ±2, ν9 ±1+ν10 ±1, 2ν10 ±2 of gaseous allene-d4 have been studied at a resolution near 0·05 cm-1. Sets of spectroscopic constants for each of the vibrations are determined, as well as the Coriolis interaction parameter which couples all three levels. The relative magnitudes and signs of the intensity parameters of the band system have been derived from contour simulations. A number of local perturbations are discussed qualitatively.