Theoretical Studies on the Structures,Stabilities,Vibrational Spectra,and Thermodynamic Properties of Polyn itromethylbenzenes

摘要

The nitro derivatives of methylbenzenes were optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G* level.The structure parameters,such as the C-NO2 bond length(LC-NO2)and the least C-NO2 bond overlap population(MC-NO2)were focused to predict their relative stability or sensitivity.Their IR spectra were obtained and assigned by vibrational analysis,which are reliable compared with the experimental results.Based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics,the thermodynamic properties were evaluated,which are linearly related with the number of nitro and methyl groups as well as the temperature,obviously showing good group additivity.