title: Molecular structures and vibrational frequencies of 2-, 3- and 4-pyridine carboxaldehydes by ab initio Hartree-Fock and density functional theory calculations.
abstract: The optimised molecular structures, vibrational frequencies and corresponding vibrational assignments of the cis and trans conformers of 2-, 3- and 4-pyridine carboxaldehydes have been calculated using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-311++G(d, p) basis set. The calculations were adapted to the C(S) symmetries of all the molecules. The mean vibrational deviations between the vibrational frequency values of the two conformers of all the compounds have been seen to increase while the relative energies increase and it was concluded the more different the molecular structure of the two conformers is the higher the relative energy is between them, and thus a bigger mean vibrational deviation.
authors.affiliation: Department of Physics, Faculty of Arts and Sciences, Süleyman Demirel University, Isparta, Turkey.
authors.forename: Adnan
authors.initials: A
authors.lastname: Sağlam
authors.forename: Fatih
authors.initials: F
authors.lastname: Ucun
authors.forename: Vesile
authors.initials: V
authors.lastname: Güçlü
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D008432:Mathematical Computing; D015394:Molecular Structure; D011725:Pyridines / Q000737:chemistry*; D014732:Vibration
chemical_list: D000447:Aldehydes; D011725:Pyridines