Infrared Spectra of CH2N2 and CD2N2

The infrared spectra of CH2N2 and CD2N2 have been investigated in the gas phase between 4500 and 400 cm−1 using a Perkin-Elmer spectrometer with LiF, NaCl, and KBr prisms. The spectra have been correlated with a planar, nonlinear configuration for the diazomethane molecule with symmetry C2v. The perpendicular type bands for both molecules are all overlapped or perturbed by neighboring absorption bands, so that no accurate values for the least moments of inertia have been obtained. Two alternative schemes of assignments for the vibrational frequencies have been proposed and the thermodynamic functions for CH2N2 computed. Potential-function calculations have been carried out.