https://doi.org/10.1140/epje/i2009-10496-4
Regular Article
Concentration and temperature dependence of the refractive index of ethanol-water mixtures: Influence of intermolecular interactions
1
Instituto de Ciencia de Materiales de Madrid (C.S.I.C.), Campus de Cantoblanco, E-28049, Madrid, Spain
2
Laboratoire de Physique des Matériaux, University of Luxembourg, 162a avenue de la Faïencerie, L-1511, Luxembourg, Luxembourg
3
Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condesada, C-III, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
* e-mail: rjimenez@icmm.csic.es
Received:
23
April
2009
Accepted:
15
July
2009
Published online:
4
September
2009
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.
PACS: 78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity) – / 65.20.Jk Studies of thermodynamic properties of specific liquids – / 61.20.Ne Structure of simple liquids – / 36.40.-c Atomic and molecular clusters –
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2009
