Concentration and temperature dependence of the refractive index of ethanol-water mixtures: Influence of intermolecular interactions.
English
Jiménez Riobóo, R.[Instituto de Ciencia de Materiales de Madrid (C.S.I.C.), Campus de Cantoblanco, E-28049-Madrid, Spain]
Philipp, Martine[University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
Ramos, M.[Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condesada, C-III, Universidad Aut´onoma]
Krüger, Jan-Kristian[University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
[en] The temperature and concentration dependence of the refractive index, n D(x, T) , in ethanol-water mixtures agrees with previous data in the ethanol-rich concentration range. The refractive index versus concentration x determined at 20 ° C shows the expected maximum at about 41 mol% water (22 mass% water). The temperature derivative of the refractive index, dn D /dT, shows anomalies at lower water concentrations at about 10 mol% water but no anomaly at 41 mol% water. Both anomalies are related to intermolecular interactions, the one in nD seems to be due to molecular segregation and cluster formation while the origin of the second one in dn D /dT is still not clear.