title: Molecular structure and vibrational spectra of N-acetylglycine oligomers and polyglycine I using DFT approach.
abstract: We have determined the geometric, vibrational, and electronic properties of N-acetylglycine oligomers by performing density functional theory quantum chemical calculations. The normal mode analysis was performed and the potential energy distribution was calculated among the internal coordinates. The optically active vibrational modes of PGI have been determined by selecting the modes from the calculated results of the pentamer and the observed vibrational spectra of PGI have been explained. The molecular electrostatic potential surface of N-acetylglycine pentamer reveals the sites of electrophilic attack and also provides clues for the role of electrostatic interactions involved in the reactivity. Natural bond orbital analysis has been performed to understand the charge transfer and various hyperconjugative interactions in the molecular system. The electronic properties of the oligomers have been discussed by calculating the transitions with the help of time dependent density functional theory method. The global reactivity descriptors such as hardness, chemical potential, and electrophilicity index have also been calculated.
authors.affiliation: Department of Applied Physics, Institute of Engineering and Technology, M. J. P. Rohilkhand University, Bareilly, India.
authors.forename: Saba
authors.initials: S
authors.lastname: Bee
authors.forename: Neetu
authors.initials: N
authors.lastname: Choudhary
authors.forename: Archana
authors.initials: A
authors.lastname: Gupta
authors.forename: Poonam
authors.initials: P
authors.lastname: Tandon
mesh_terms: D000465:Algorithms; D019295:Computational Biology / Q000379:methods; D018360:Crystallography, X-Ray; D004583:Electrons; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009842:Oligopeptides / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D055672:Static Electricity; D013816:Thermodynamics; D014732:Vibration
chemical_list: D009842:Oligopeptides; D010455:Peptides; C011080:polyglycine; D005998:Glycine; C006368:aceturic acid
keywords: Polyglycine I; oligomer; vibrational spectroscopy