CASPIAN JOURNAL
MANAGEMENT AND HIGH TECHNOLOGIES
System analysis of structural and dinamic models of azauracil dimers in condensed state
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Read | Erman Evgeny A., Stefanova Galina P., Dzhalmukhambetova Elena A., Grechukhina Oksana N, Alykova Olga M., Ravcheeva Natalya A. System analysis of structural and dinamic models of azauracil dimers in condensed state // Caspian journal : management and high technologies. — 2012. — №3. — pp. 95-102. |
Erman Evgeny A. - Ph.D. (Engineering), Astrakhan State University, 20a Tatishchev st., Astrakhan, 414056, Russia,, kof@aspu.ru
Stefanova Galina P. - D.Sc. (Pedagogics), Professor, Astrakhan State University, 20a Tatishchev st., Astrakhan, 414056, Russia,, kof@aspu.ru
Dzhalmukhambetova Elena A. - Ph.D. (Physics and Mathematics), Astrakhan State University, 20a Tatishchev st., Astrakhan, 414056, Russia,, kof@aspu.ru
Grechukhina Oksana N - Senior Lecturer, Astrakhan State University, 20a Tatishchev st., Astrakhan, 414056, Russia,, kof@aspu.ru
Alykova Olga M. - Ph.D. (Pedagogics), Astrakhan State University, 20a Tatishchev st., Astrakhan, 414056, Russia,, kof@aspu.ru
Ravcheeva Natalya A. - Lecturer, Astrakhan State University, 20a Tatishchev st., Astrakhan, 414056, Russia,, kof@aspu.ru
Structural and dynamic models of 5- and 6-azauracils are proposed on the basis of ab initio quantum calculations of geometric and electronic structure. The parameters of adiabatic potential are determined, the interpretation of vibrational states of the test compound is proposed. The analysis of molecule structure of the substance is carried out. The method for calculating the shift of vibrational bands of azauracil dimers based on perturbation theory of the second order is presented. A choice of method and basis for calculation of fundamental vibration frequencies and intensities of the bands in the IR and Raman spectra is justified. The technique for evaluation of anharmonicity with cubic and quartic force constants is described. The paper presents the results of numerical experiments, geometric parameters of molecules, such as the valence bond lengths and angles between them. We obtain the frequency of the vibrational states and values of their integrated intensities. The interpretation of monomer vibrations is given. The results are in good agreement with experimental values. The frequencies that can be used to identify the compounds of the vibrational spectra of molecules are proposed. The calculation was carried out by quantum density functional method DFT/B3LYP. It is shown that this method can be used to model the geometrical parameters of molecular and electronic structure of various benzole-substituted. It allows us to construct the structural and dynamic models of this class of compounds by numerical calculations.
Key words: Azauracil,5-azauracil,6-azauracil,Dimer,Vibrational spectra,IR spectra,Raman spectra,Anharmonic shift,Adiabatic potential,Hydrogen bond