title: Spectroscopic analysis of cinnamic acid using quantum chemical calculations.
abstract: In this present study, FT-IR, FT-Raman, (13)C NMR and (1)H NMR spectra for cinnamic acid have been recorded for the vibrational and spectroscopic analysis. The observed fundamental frequencies (IR and Raman) were assigned according to their distinctiveness region. The computed frequencies and optimized parameters have been calculated by using HF and DFT (B3LYP) methods and the corresponding results are tabulated. On the basis of the comparison between computed and experimental results assignments of the fundamental vibrational modes are examined. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by HF and DFT methods. The alternation of the vibration pattern of the pedestal molecule related to the substitutions was analyzed. The (13)C and (1)H NMR spectra have been recorded and the chemical shifts have been calculated using the gauge independent atomic orbital (GIAO) method. The Mulliken charges, UV spectral analysis and HOMO-LUMO analysis of have been calculated and reported. The molecular electrostatic potential (MEP) was constructed.
authors.affiliation: Department of Physics, Indira Gandhi Polytechnic College, Mahe, UT-Puducherry, India; Research Scholar, Bharathiar University, Coimbatore, Tamil Nadu, India.
authors.forename: K S
authors.initials: KS
authors.lastname: Vinod
authors.affiliation: Department of Physics, Tagore Arts College, Puducherry, India.
authors.forename: S
authors.initials: S
authors.lastname: Periandy
authors.affiliation: Department of Physics, Bharathidasan College for Women, Puducherry, India. Electronic address: govindarajan64@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Govindarajan
mesh_terms: D002934:Cinnamates / Q000737:chemistry*; D019281:Dimerization; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity
chemical_list: D002934:Cinnamates; C029010:cinnamic acid
keywords: Cinnamic acid; DFT; GIAO; HOMO; LUMO