where, fresnel reflectivity, is reflectivity calculated for an ideal, zero width, steplike interface,and is the z component of wave vector transfer with respect to the lower phase.the critical wave vector transfer Qc is given by the bulk densities as Qc, in agreement with our experimental measurement. the data for each interface are separately fit to EP2. , and the resulting fit parameters, are listed in table i. although more complicated models of the interfacial structure can be proposed, the data are well represented by this simple model.
in the spirit of a hybrid model of the interface that describes an intrinsic structure profile roughened by capillary waves, the intefacial width,can be represented as a combination of an intrinsic profile width,and a resolution dependent,capillary-wave contribution.