Force field and assignment of the vibrational spectra of quinoline and isoquinoline - An ab initio study

The force field and vibrational spectra of quinoline and isoquinoline with Cs symmetry are studied at Hartree Fock level of theory using 6-31G** basis set. The scaled non-redundant local force constants and the corresponding scale factors obtained after fitting the ab initio vibrational frequencies of quinoline to the experimental ones are presented. The scale factors are transferred to predict the fundamentals of isoquinoline. The predicted numb ers agree well with the experimental numbers. The force fields and vibratio nal spectra of naphthalene, quinoline and isoquinoline reveal that they are structurally similar.