title: Molecular structure, vibrational, UV, NMR, hyperpolarizability, NBO and HOMO-LUMO analysis of Pteridine2,4-dione.
abstract: The FTIR and FT-Raman spectra of Pteridine2,4-dione has been recorded in the region 4000-450 and 4000-100 cm(-1), respectively. The tautomeric stability, optimized geometry, frequency and intensity of the vibrational bands of Pteridine2,4-dione were obtained by the density functional theory (DFT) using 6-311++G(d,p) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The (1)H and(13)C NMR spectra chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. The theoretical UV-Vis spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The first order hyperpolarizability (β(0)) of these novel molecular system and related properties (β, α(0) and Δα) of Pteridine2,4-dione are calculated using DFT/6-311++G (d,p) method on the finite-field approach. The Mulliken charges, the values of electric dipole moment (μ) of the molecule were computed using DFT calculations. The change in electron density (ED) in the σ(*) antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions.
authors.affiliation: Department of Physics, Sri Sarada College for Women (Autonomous), Salem 636 016, India. n.prabavathi@yahoo.co.in
authors.forename: N
authors.initials: N
authors.lastname: Prabavathi
authors.forename: A
authors.initials: A
authors.lastname: Nilufer
authors.forename: V
authors.initials: V
authors.lastname: Krishnakumar
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011621:Pteridines / Q000737:chemistry*; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics
chemical_list: D011621:Pteridines