FT-IR and FT-Raman spectral studies and DFT calculations of tautomeric forms of benzaldehyde-N(4)-phenylsemicarbazone

The vibrational wave numbers of the keto and enol forms of benzaldehyde-N(4)-phenylsemicarbaione have been computed using B3LYP/6-311++G** level of theory and compared with experimental FT-IR and FT-Raman data. Optimized geometrical parameters of the title compound are in agreement with the reported structures. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is. an attractive object for future studies on non-linear optics. The extended pi-electron delocalization over the semicarbazone moiety is responsible for the nonlinearity of the molecule.