Density Functional Theory and Abinitio Studies of Vibrational Spectra of Nalidixic Acid

Abstract

The FTIR and FTR spectrum of Nalidixic acid has been recorded in the region of 4000-400 cm-1 and 3500-250cm-1, respectively.
The optimized geometry, frequency and intensity of the vibrational bands of Nalidixic acid were obtained by ab initio and DFT levels of theory with complete relaxation in the potential energy surface using 6-31G(d,p) basis set. A Complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed. The harmonic vibrational frequencies calculated have been compared with experimental FTIR and FT Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theretically constructed bar type spectrograms.