Ellipsometric determination of universal critical adsorption scaling functions

In this paper we determine and compare a number of theoretical models which describe the universal scaling functions for critical adsorption in the st rong surface field limit. The P1 and P3 models, which are continuous up to and including the first and third derivatives, respectively, provide excell ent descriptions of the ellipsometric data for four different critical bina ry liquid mixtures. The exponential-Pade model, initially proposed by Liu a nd Fisher [Phys. Rev. A 40, 7202 (1989)], provides a reasonable but less ac curate description of the one-phase experimental data. This later model has the advantage, however, that it is continuous in all derivatives. PACS num ber(s): 68.35.Rh, 68.10.-m, 64.60.Fr, 82.65.Dp.