Rotational spectrum and structure of the complex HCNCO2

Abstract

Radiofrequency and microwave rotational spectra of the complexes HCN CO₂ and DCN CO₂ have been obtained using molecular beam electric resonance spectroscopy. The spectra are characteristic of prolate asymmetric rotors. The spectroscopic constants obtained are These are shown to be consistent with a C_2v structure in which the nitrogen of the HCN bonds to the carbon of the CO₂ with a weak bond length of 3.00 Å. The HCN subunit subtends an average angle of 17.4 (2)° with the line joining the centers of mass of the two submolecules, and the average bending vibrational amplitude of the CO₂ is 11(1)°. The difference between the average amplitudes of the in‐plane and out‐of‐plane bending vibrations of the HCN is less than 4°. The stretching force constant for the weak bond is 0.049 mdyne/Å in HCNCO₂, and the induced dipole moment is 0.361 D.