Density Functional Theory Study of Vibrational Spectra. 2. Assignment of Fundamental Vibrational Frequencies of Fulvene

Ab initio restricted Hartree-Fock (RHF) and density function theory calculations using Becke\u27s exchange and Lee-Yang-Parr\u27s correlation functionals (BLYP) were carried out to study the molecular structure and vibrational spectrum of fulvene. Comparison of the calculated and experimental results indicates the density functional BLYP/6-31G* method is more accurate in predicting fundamental vibrational frequencies than the scaled Hartree-Fock approach. On the basis of the calculated results, reassignment of some fundamental vibrational modes of fulvene is proposed. This study shows that density functional theory is a very promising method for understanding the vibrational spectra of organic compounds