title: Comparative vibrational spectroscopic studies, HOMO-LUMO, NBO analyses and thermodynamic functions of p-cresol and 2-methyl-p-cresol based on DFT calculations.
abstract: In the present study structural properties of p-cresol, and 2-methoxy-p-cresol have been studied by using B3LYP/cc-pvdz and B3PW91/cc-pvdz of Density Functional Theory (DFT) utilizing Becke three exchange functional and Lee Yang Paar correlation functional. The Fourier transform infrared and Fourier transform Raman spectra of title molecules were recorded (solid phase). Optimized geometry, harmonic vibrational frequencies and various thermodynamic parameters of the title compounds were calculated with B3LYP/cc-pvdz, and B3PW91/cc-pvdz basis sets. Non-linear optical (NLO) behavior of the p-cresol and 2-methoxy-p-cresol were investigated by determining of electric dipole moment, polarizability α, and hyperpolarizability β using the above mentioned basis sets. The molecular properties such as ionization potential, electronegativity, chemical potential, electrophilicity have been deduced from HOMO-LUMO analysis employing the same basis sets. A detailed interpretation of the infrared and Raman spectra of title molecules were reported. UV spectrum was measured in different solvent. The energy and oscillator strength are calculated by Time Dependant Density Functional Theory (TD-DFT) results. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. The complete assignments were performed on the basis of the potential energy distribution (PED) of vibrational modes, calculated with scaled quantum mechanics (SQM) method. Finally the theoretical FT-IR, FT-Raman, and UV spectra of the title molecules have also been constructed.
authors.affiliation: Department of Physics, Arignar Anna Government Arts College, Musiri, Tiruchirappalli 621211, India. Electronic address: brsbala@rediffmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Balachandran
authors.affiliation: Department of Physics, Govt. Arts College, Tiruchirappalli 620022, India.
authors.forename: M
authors.initials: M
authors.lastname: Murugan
authors.affiliation: Department of Physics, SRM University, Ramapuram, Chennai 600089, India.
authors.forename: A
authors.initials: A
authors.lastname: Nataraj
authors.affiliation: Department of Physics, Srimad Andavan Arts and Science College, Tiruchirappalli 620005, India.
authors.forename: M
authors.initials: M
authors.lastname: Karnan
authors.affiliation: Department of Physics, M.I.E.T. Engineering College, Tiruchirappalli 620007, India.
authors.forename: G
authors.initials: G
authors.lastname: Ilango
mesh_terms: D003408:Cresols / Q000737:chemistry*; D004560:Electricity; D004583:Electrons; D008958:Models, Molecular; D008968:Molecular Conformation; D017711:Nonlinear Dynamics; D055620:Optical Phenomena; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013816:Thermodynamics; D014732:Vibration
chemical_list: D003408:Cresols; C032538:4-cresol
keywords: 2-Methoxy-p-cresol; Electrostatic potential; Hyperpolarizability; NBO analysis; p-Cresol