High-resolution infrared study of 1,1-ethylene-D 2 in the 2000- to 1200-cm -1 region

The infrared spectrum of H ₂CCD ₂ was investigated in the region 2000-1200 cm ^-1 at a resolution of ∼0.05 cm ^-1. Complete analyses of four type- A bands are reported-the CC stretch, ν₂, the CH ₂ deformation, ν₁₂, and the overtones of the CD ₂ and CH ₂ wagging fundamentals, 2 ν₇ and 2 ν₈. Localized perturbations are identified and taken into account in the analyses, enabling the perturbing vibrational levels to be located accurately and the interaction parameters to be determined. In the case of ν₁₂, Fermi resonance with 2 ν₁₀ has a global effect, and causes a bandhead to be formed in the K_a subband series.