THE VIBRATIONAL FORCE-FIELD OF DIAZIRINE FROM GAS-PHASE DATA AND FROM AB-INITIO CALCULATIONS

Vibrational band centers from five isotopic species (parent species H2CN2, all symmetrically substituted species and HDCN2), centrifugal distortion constants also from five isotopic species (parent species, all symmetrically substituted species and (H2CNN)-N-15)), and information about the Fermi resonance between nu2 and 2nu7 from matrix data have been combined to obtain an experimental force field of diazirine. Since diazirine represents an unusual bonding situation, an ab initio force field was also determined. The uniqueness of the transformation from cartesian to valence coordinates is discussed. Information from the ab initio force field was used in obtaining an optimal force field from the experimental data.