RAMAN-SPECTRA OF THE DIMETHYL ETHER ... HYDROGEN-CHLORIDE HYDROGEN-BONDED COMPLEX IN THE GAS-PHASE

The Raman spectra of the hydrogen-bonded complexes formed between (CH 3)2O or (CD3)2O and HCl or DCl have been recorded in the gas phase at room temperature. The Raman profiles of the νClH and νClD stretching vibrations are found to be different from the corresponding infrared ones. It is suggested that, in addition to the rather strong mechanical anharmonicity which couples the νClH and νClH⋯O modes, electrical anharmonicity and coupling with other low-frequency deformation modes of the hydrogen bond, could explain the observed spectral differences. Other band-shaping mechanisms such as Fermi resonances with overtones and combinations involving the ethereal part or rotational broadening seem to be of secondary importance since only small differences are observed on the Raman spectra respectively when (CH3)2O is changed by (CD 3)2O or when the spectrum of a given complex is taken in the IVV or IVH geometries. © 1979 American Institute of Physics.