title: Quantum chemical density functional theory studies on the molecular structure and vibrational spectra of mannitol.
abstract: A collective experimental and theoretical study was conducted on the molecular structure and vibrational spectra of mannitol. The FT-IR and FT-Raman spectra of mannitol were recorded in the solid phase. The molecular geometry, vibrational frequencies, thermodynamic functions and atomic charges of mannitol in the ground state have been calculated by using the ab initio HF (Hartree-Fock) and density functional methods (B3LYP) invoking cc-pVDZ basis set. The complete vibrational assignments were performed on the basis of Total Energy Distribution (TED) of the vibrational modes. The UV absorption spectra of the title compound dissolved in water. Natural bond orbital analysis has been carried out to explain the charge transfer or delocalization of charge due to the intra-molecular interactions. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by GIAO methods. The first order hyperpolarizability (β0) of this novel molecular system and related properties (β, α0 and Δα) of mannitol are calculated using B3LYP/cc-pVDZ and HF/cc-pVDZ methods on the finite-field approach. By using TD-DFT calculation, electronic absorption spectra of the title compound have been predicted and a good agreement with experimental one is established. In addition, the molecular electrostatic potential (MEP) have been investigated using theoretical calculations, the calculated HOMO and LUMO energies shows that the charge transfer within the molecule.
authors.affiliation: PG and Research Department of Physics, Pachaiyappa's College, Chennai 600030, TN, India; Department of Physics, C. Kandaswami Naidu College for Men in Anna Nagar East, Chennai 600102, TN, India.
authors.forename: P P
authors.initials: PP
authors.lastname: Moorthi
authors.affiliation: Research and Development, St. Peter's Institute of Higher Education and Research, St. Peter's University, Avadi, Chennai 600054, TN, India.
authors.forename: S
authors.initials: S
authors.lastname: Gunasekaran
authors.affiliation: Department of Textile Technology, Anna University, Chennai 600025, TN, India.
authors.forename: S
authors.initials: S
authors.lastname: Swaminathan
authors.affiliation: Department of Physics, C. Kandaswami Naidu College for Men in Anna Nagar East, Chennai 600102, TN, India. Electronic address: gr.ramkumaar@yahoo.com.
authors.forename: G R
authors.initials: GR
authors.lastname: Ramkumaar
mesh_terms: D002244:Carbon / Q000737:chemistry; D019277:Entropy; D006859:Hydrogen / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008353:Mannitol / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013696:Temperature; D013816:Thermodynamics; D014732:Vibration
chemical_list: D008353:Mannitol; D002244:Carbon; D006859:Hydrogen
keywords: DFT; FT-IR; MEP surface; Vibrational analysis