Calculations of the structure, vibrational spectrum and thermodynamic properties of succinimide

Density functional theory(DFT) and ab initio molecular orbital method have been employed to optimize the molecular geometry of succinimide at the B3LYP/6-31G*, B3LYP/6-311G** and MP2/6-311G** levels, respectively. Harmonic vibrational analyses have been performed at the B3LYP/6-31G* and B3LYP/6-311G** levels. The standard thermodynamic properties at various temperatures have been evaluated using the scaled B3LYP/6-31G* and B3LYP/6-311G** frequencies. The calculated results are compared with each others and with available experimental data, and are discussed in detail.