engleski

On the existence of a scattering pre-peak in the mono-ols and diols

Associating liquids, such as water and alcohols, exhibit a wealth of structural organization at the microscopic level. The existence of specific structuring in neat mono-ols [1] has been pointed out by the results of scattering experiments on those alcohols, which have revealed a pre-peak in scattering intensity [2]. With the increase of alkyl chain length, the pre-peak in scattering intensity becomes more prominent [2], showing the increase of chain-like clusters. But what happens in alcohols which have two hydroxyl groups bound by an alkyl chain? In this work, we are looking into four neat 1, n-diols (1, 2-ethanediol to 1, 5-pentanediol), which were studied by means of molecular dynamics simulations. Radial distribution functions, site-site structure factors, cluster size distribution probabilities and calculated X-ray intensities are reported and compared with corresponding mono-ols [3]. It's found that in diols, just like in monools, the increase in carbon chain length leads to an increase in the hydroxyl group associations. However, our calculated X-ray intensities show that the pre-peak tends to iminish to a shoulder, which is in variance with monools. We attribute this contrasting finding to the fact that the alkyl chain is constrained between the two hydroxyl groups in linear diols, while they are free in linear mono-ols. [1] A. Perera, F. Sokolic, L. Zoranic, Phys. Rev. E 75 060502-(R) (2007) [2] M. Tomšič, A. Jamnik, G. Fritz-Popovski, O. Glatter and L. Vlcek, J. Phys. Chem. B 111, 1738 (2007). [3] M. Požar and A. Perera, CPLett 671, 37 (2017)

computer-simulations, alcohols, diols, monools, structure-factor, scattering-intensity, pre-peak

nije evidentirano