The Stokes-Einstein relation in water/methanol solutions

C Corsaro; E Fazio; D Mallamace

doi:10.1063/1.5096760

The Stokes-Einstein relation in water/methanol solutions

J Chem Phys. 2019 Jun 21;150(23):234506. doi: 10.1063/1.5096760.

Authors

C Corsaro¹, E Fazio¹, D Mallamace¹

Affiliation

¹ Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, Viale F. Stagno d' Alcontres, 31, 98166 Messina, Italy.

PMID: 31228897
DOI: 10.1063/1.5096760

Abstract

The hydrogen bonding ability of both water and methanol, together with the occurrence of hydrophobic interactions, makes their solutions nonideal. This nonideality is reflected in both dynamic and thermodynamic quantities at different extent depending on temperature and concentration. The thermal behavior in terms of transport quantities is investigated for different methanol molar fractions by using the concepts of the Stokes-Einstein relation. Starting from the pure compounds, we compare self-diffusion and viscosity data as a function of the temperature for methanol molar fractions X_MeOH = 0.22, 0.5, and 0.7. The results are interpreted within the scenario of the mode coupling theory and show that the Stokes-Einstein relation is violated in a different way depending on the solution concentration.