AB-INITIO CALCULATIONS OF THE STRUCTURE AND HARMONIC FORCE-FIELDS FORTHE AMINE FORMS OF DINITRAMINE AND METHYLDINITRAMINE - VIBRATIONAL-SPECTRA AND THEIR INTERPRETATION USING A SCALING PROCEDURE

At, initio geometries and vibrational spectra have been calculated for the amine structures of dinitramine and methyldinitramine, HN(NO2)(2) and CH3N(NO2)(2) It is Shown at the RHF and MP2 levels with the use o f the 6-31G and 6-31G** basis sets that these molecules have differen t symmetries in their equilibrium states, C-s and C-1 respectively. Th e quantum chemical RHF/6-31G force fields were scaled with the set of transferable factors previously obtained by the authors to assign the available experimental vibrational bands and predict the positions of bands for the unmeasured spectral regions. Some common patterns of th e geometrical parameters, vibrational spectra, and force fields of the simplest nitramines are discussed.