CASPIAN JOURNAL
MANAGEMENT AND HIGH TECHNOLOGIES
STRUCTURAL-DYNAMIC MODELS OF HYDROXYENZOIC ACID
 |
Read | Elkin Mikhail D., Nuralieva Diana M., Likhter Anatoly M., Gordeev Ivan I., Gaisina Alfiya R. STRUCTURAL-DYNAMIC MODELS OF HYDROXYENZOIC ACID // Caspian journal : management and high technologies. — 2011. — №3. — pp. 77-85. |
Elkin Mikhail D. - D.Sc. in Physics, Full Professor, Astrakhan State University, 20a Tatishchev str., Astrakhan, 414056, Russia, elkinmd@mail.ru.
Nuralieva Diana M. - Postgraduate student, Astrakhan State University, 20a Tatishchev str., Astrakhan, 414056, Russia, kof1@aspu.ru.
Likhter Anatoly M. - D.Sc. in Technics, Astrakhan State University, 20a Tatishchev str., Astrakhan, 414056, Russia, kof@aspu.ru.
Gordeev Ivan I. - Senior Lecturer, Astrakhan State University, 20a Tatishchev str., Astrakhan, 414056, Russia, g2i@mail.ru.
Gaisina Alfiya R. - Lecturer, Astrakhan State University, 20a Tatishchev str., Astrakhan, 414056, Russia, gaisinaalfiya@mail.ru.
The structural-dynamic models of hydroxybenzoic acid are made with consideration of anharmonic effects. Model calculations of geometrical structure and electronic structure of p-, m-, and o-hydroxybenzoic acid is carried out by the hybrid method DFT/B3LYP with basis 6-311G**. Interpretation of vibrational states of hydroxybenzoic acid monomers and dimers is given on the basis of modeling not empirical quantum calculations of adiabatic potential. The estimation procedure for anharmonic shift of vibrational lines in hydroxybenzoic acid is described. It based on results of ab initio quantum calculations of anharmonic cubic and quartic force constants. The estimation of the mechanism intramolecular and intermolecular interaction for hydroxybenzoic acid monomers and dimers is given. The influence of intermolecular interaction is estimated for shift of vibrational lines. Influence of a relative positioning of hydroxyl and carboxyl fragments on frequencies of fundamental vibrations for p- and m-hydroxybenzoic acid can be neglected according to modeling calculations. Some difference is in borders of criterion of reliability of predictive calculations for fundamental vibrational states of polyatomic molecules (~10 cm-1). Exception is made with a strip interpreted as torsional vibration of hydroxyl fragment.
Key words: vibrational spectra,anharmonicity of vibration,hydroxybenzoic acid,adiabatic potential,intermolecular and intramolecular interaction.