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Journal of Spectroscopy
Volume 2013, Article ID 171735, 18 pages
Research Article

Molecular Structure, NMR, HOMO, LUMO, and Vibrational Analysis of O-Anisic Acid and Anisic Acid Based on DFT Calculations

1Department of Physics, Sri Sarada College for Women (Autonomous), Salem 636016, India
2Department of Physics, Vivekanandha College of Arts and Sciences (W), Namakkal 637205, India
3Department of Physics, Bharathiyar Arts & Science College (W), Salem 636112, India

Received 1 May 2013; Accepted 14 July 2013

Academic Editor: Renata Diniz

Copyright © 2013 R. Mathammal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This work deals with the vibrational spectroscopy of O-Anisic acid (OAA) and Anisic acid (AA). The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT) with standard B3LYP/6-31G** method and basis set combinations. The vibrational spectra were interpreted, with the aid of normal coordinate analysis based on a scaled quantum mechanical force field. The infrared and Raman spectra were also predicted from the calculated intensities. The effects of carbonyl and methyl substitutions on the structure and vibrational frequencies have been investigated. Comparison of simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes. The 13C and 1H NMR chemical shifts of the DFA and CA molecules were calculated using the gauge-invariant-atomic orbital (GIAO) method in DMSO solution using IEF-PCM model and compared with experimental data.