title: Spectroscopic and quantum chemical analysis of Isonicotinic acid methyl ester.
abstract: In this present study, an organic compound Isonicotinic acid methyl ester (INAME) was structurally characterized by FTIR, FT-Raman, and NMR and UV spectroscopy. The optimized geometrical parameters and energies of all different and possible conformers of INAME are obtained from Density Functional Theory (DFT) by B3LYP/6-311++G(d,p) method. There are three conformers (SI, SII-1, and SII-2) for this molecule (ground state). The most stable conformer of INAME is SI conformer. The molecular geometry and vibrational frequencies of INAME in the ground state have been calculated by using HF and density functional method (B3LYP) 6-311++G (d,p) basis set. Detailed vibrational spectral analysis has been carried out and assignments of the observed fundamental bands have been proposed on the basis of peak positions and relative intensities. The computed vibrational frequencies were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. A study on the electronic properties, such as HOMO and LUMO energies were performed by time independent DFT approach. Besides, molecular electrostatic potential (MEP) and thermodynamic properties were performed. The electric dipole moment (μ) and first hyper polarizability (β) values of the investigated molecule were computed using ab initio quantum mechanical calculations. The calculated results show that the INAME molecule may have microscopic nonlinear optical (NLO) behavior with non zero values. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by gauge independent atomic orbital (GIAO) method.
authors.affiliation: Department of Physics, Periyar Maniammai University, Thanjavur, India; Department of Physics, Alpha College of Engineering & Technology, Puducherry, India.
authors.forename: D
authors.initials: D
authors.lastname: Shoba
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 Government College for Women, Puducherry, India. Electronic address: govindarajan64@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Govindarajan
authors.affiliation: Department of Physics, Periyar Maniammai University, Thanjavur, India.
authors.forename: P
authors.initials: P
authors.lastname: Gayathri
mesh_terms: D066241:Carbon-13 Magnetic Resonance Spectroscopy; D002725:Chloroform / Q000737:chemistry; D003198:Computer Simulation; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004583:Electrons; D007536:Isomerism; D007539:Isonicotinic Acids / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D017711:Nonlinear Dynamics; D066244:Proton Magnetic Resonance Spectroscopy; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013816:Thermodynamics; D014732:Vibration
chemical_list: D007539:Isonicotinic Acids; D012997:Solvents; D002725:Chloroform; D004121:Dimethyl Sulfoxide
keywords: DFT; HF; HOMO; LUMO; Vibrational analysis