Raman spectra and vibrational potential function of polycrystalline azomethane and azomethane-d6

Raman spectra of polycrystalline azomethane (CH3N=NCH3) and azomethane-d6 were examined at liquid nitrogen temperatures using argon ion laser excitation. These data, in conjunction with a normal coordinate analysis, provide a basis for a modification of the vibrational assignments for the azomethane system. A 17 parameter molecular force field, based upon the solid state vibrational frequencies of azomethane and its deuterated analog, was determined by least-squares procedures. The unusual coupling characteristics between the X–N stretching and X–N=N bending coordinates are discussed for both azomethane and trans-1,2-difluorodiazine, FN=NF.