A High-Resolution Fourier Transform Infrared Study of the ν3, ν4, and ν5 Bands of Deuterated Formyl Chloride (DCOCl)

High-resolution infrared spectra of the low-lying ν₃, ν₄, and ν₅ fundamentals of the transient molecule DCOCl are reported. These type-A/B hybrid bands have been analyzed in detail, providing extensive rotational assignments for the DCO³⁵Cl and DCO³⁷Cl isotopomers. The ground state constants have been refined by a simultaneous fit of the available microwave data and FTIR combination differences from the three bands. The excited state constants have been determined by fitting assignments over a wide range of J and K_a values. A small perturbation was found at high K_a values in the ν₄ band and determined to be due to a ΔK_a = −2 interaction with the rotational levels of the 6¹ vibrational state.