Effects of molecular de-aggregation on refractive indices of petroleum-based fluids

It is conventionally assumed that refractive index (RI) for a crude oil, a processed fuel or any petroleum-based solution may be evaluated in an assumption of an ideal binary mixture of non-precipitating components. However, new experimental data reveal strong non-ideality of RI in dilute oil solutions, which we attribute to de-aggregation of asphaltenes.