QUANTUM-CHEMICAL INVESTIGATION OF STRUCTURES, ROTATIONAL BARRIERS, AND VIBRATIONAL-SPECTRA OF THE ROTAMERS OF ETHYL NITRITE (CH3CH2ONO)

Ab initio and density functional (DFT) methods were used to investigat e the rotamers of ethyl nitrite. The potential energy surface for rota tions around the C-O and the N-O bonds was calculated at different lev els of theory. From the four geometrically possible conformers, only t hree were found to be stable when correlation effects are taken into a ccount in the calculations. This result is consistent with a microwave study of Turner (J. Chem. Soc., Faraday Trans. 2 1979, 317.) as well as with the presented IR spectrum of matrix-isolated ethyl nitrite whi ch clearly distinguishes three different N=O stretching modes. A simul ated IR spectrum generated from the results of the DFT calculations is in good agreement with this matrix spectrum and allows us to tentativ ely assign groups of frequencies.