Matt D. Brown

Comparison of critical adsorption scaling functions obtained from neutron reflectometry and ellipsometry.

Carpenter et al. [Phys. Rev. E 59, 5655 (1999); 61, 532 (2000)] managed to explain ellipsometric critical adsorption data collected from the liquid-vapor interface of four different critical binary liquid mixtures near their demixing critical temperature using a single model. This was the first time a single universal function had been found which could quantitatively describe the surface critical behavior of many different mixtures. There have also been various attempts to investigate this surface critical behavior using neutron and x-ray reflectometries. Results have been mixed and have often been at variance with Carpenter et al. In this paper, the authors show that neutron reflectometry data collected from a crystalline quartz-critical mixture interface, specifically deuterated water plus 3-methylpyridine, can be quantitatively explained using the model of Carpenter et al. derived from ellipsometric data.

Ultra-stable oven designed for x-ray reflectometry and ellipsometry studies of liquid surfaces

Stable temperature control is highly desirable for reflectivity studies of binary liquid mixtures. In this article we report on the construction of an oven that possesses good temperature stability (∼1 mK/day) and small transverse temperature gradients (<1 mK/cm). The oven has a horizontal geometry and can be used for either x-ray reflectometry or ellipsometry measurements from the liquid/vapor surfaces of such systems. Details of the oven design together with test results are provided.