Local mode assignments for the CD-stretching overtone spectra of deuterated methyl iodide and deuterated methyl cyanide: effects of increased interoscillator coupling on local mode states of C3v symmetry

Abstract

The overtone spectra of CD3I and CD3CN are measured at room temperature in the liquid phase in the regions of CD-stretching local mode overtones corresponding to ΔvCD = 2–5. The spectra are analyzed in terms of a harmonically coupled local mode model. The local mode parameters ω, ωx, and γ′v, the interoscillator coupling between the methyl CD bonds, are determined. A comparison of the spectra of the CH3Z molecules (Z = Cl, Br, I, CN) to the spectra of CD3I and CD3CN reveals the spectral effects of increased interoscillator coupling between the CD bonds.