|Title||Self-diffusion of molecules in water-ethanol solutions of low concentration. Neutron data|
|Publication Type||Journal Article|
|Year of Publication||2019|
|Authors||Vasylkevych, OA, Slisenko, VI|
|Abbreviated Key Title||Dopov. Nac. akad. nauk Ukr.|
The work is devoted to the abnormal behavior of dilute wateralcohol solutions. The dynamics of molecules of the waterethanol system, depending on the concentration at 281 K, is researched by the method of quasielastic scattering of slow neutrons. The total selfdiffusion coefficient of molecules D, its singleparticle Ds-p and collective Dcoll components, and the time of settled molecule’s life in the oscillating state t0 are determined. The region of small concentrations was studied in detail, and two minima in the coefficients D and Ds-p were detected in the vicinity of concentrations X = 0.04 mol.f. and X = 0.2 mol.f. Time t0 at these concentrations is increasing significantly. This indicates a significant decrease in the intensity of the activation mechanism of diffusion of molecules, which is quite possible due to the binding of water and ethanol molecules into complexes (clusters).
|Keywords||cluster, dilute aqueousalcohol solutions, ethanol, quasielastic scattering of slow neutrons, selfdiffusion coefficient, singleparticle and collective components of the selfdiffusion coefficient|
1. Vuks, M. F. (1977). Scattering of light in gases, liquids and solutions. Leningrad: Izdvo Leningr. Unta (in Russian).
2. Prigozhin, I. R. (1990). Molecular theory of solutions. Ìoscow: Metallurgiya (in Russian).
3. Chechko, V. E., Lokotosh, T. V., Malomuzh, N. P., Zaremba, V. G. & Gotsul’sky, V. Ya. (2003). Clusterization and anomalies of fluctuations in wateralcohol solutions low concentrations. J. Phys. Studies, 7, No. 2, pp. 175183 (in Ukrainian).
4. Gotsulsky, V. Ya, Chechko, V. E. & Melnik, Yu. A. (2015). The origin of light scattering by aqueous solutions of alcohols in vicinity of their singular points. J. Phys. Studies, 60, No. 8, pp. 782794 (in Ukrainian). doi: https://doi.org/10.15407/ujpe60.08.0782
5. Malomuzh, N. P. & Slipchak, E. L. (2007). The cluster structure of dilute aqueousalcohol solutions and the features of molecular light scattering in them. J. Phys. Chem., 81, No. 11, pp. 16 (in Russian). doi: https://doi.org/10.1134/S0036024407110106
6. Parfit, G. D. & Wood, J. F. (1968). Light scattering from binary mixtures of water, methanol, and ethanol. Trans. Faraday Soc., 64, pt. 8, pp. 20812091. doi: https://doi.org/10.1039/tf9686402081
7. Vuks, M. F. & Shurupova, L. V. (1976). Light scattering and phase transitions in aqueous solutions of simple alcohols. Optika i spektposkopia, 40, pt. 1, pp. 154159 (in Russian).
8. Van Hove, L. (1954). Correlation in space and time and Born approximation scattering in systems of interacting particles. Phys. Rev., 95, No. 1, pp. 249262. doi: https://doi.org/10.1103/PhysRev.95.249
9. Van Hove, L.(1958). A remark on the timedependent pair distribution. Physica, 24, pp. 404408. doi: https://doi.org/10.1016/S0031-8914(58)95629-5
10. Oskotsky, V. S. (1963). To the theory of quasielastic scattering of cold neutrons in a liquid. Fizika tverdogo tela, 5, No. 4, pp. 10821085 (in Russian).
11. Ivanov, G. K. (1966). Inelastic and elastic scattering of neutrons by molecules. J. Exptl. Theoret. Phys. (U.S.S.R.), 50, Iss. 3, pp. 726737 (in Russian).
12. Ivanov, G.K. (1967). The role of diffusion processes in the scattering of slow neutrons in liquids. J. Exptl. Theoret. Phys. (U.S.S.R.), 51, Iss. 4, pp. 11201127 (in Russian).
13. Bulavin, L. A., Verbinskya, G. M. & Krotenko, V. V. (1991). Singleparticle and collective contributions to the selfdiffusion coefficient of methyl alcohol. Fizika zhidkogo sostoyaniya, No. 19, pp. 4043 (in Ukrainian).
14. Bulavin, L. A., Karmazina, T. V., Klepko, V. V. & Slisenko, V. I. (2005). Neutron spectroscopy of condensed media. Kyiv: Akademperiodyka.