Critical scattering of laser light by fluid films and interfaces

Technical Report · Mon Oct 01 04:00:00 EDT 1979

DOI:https://doi.org/10.2172/5755105· OSTI ID:5755105

Mockler, R C; O'Sullivan, W

Analysis of results of coexistence curve measurements for films of a 2,6-lutidine + water critical mixture, has resulted in the first general confirmation of the scaling theory description of Ising class fluid film critical behavior. For example, we have shown that (3,1) to (2,1) universality class transitions occur in these films as a result of finite size constraints upon the evolution of the correlation length, xi. There exists a generalized law of corresponding states for films. The critical temperature-shift exponent and the crossover temperature critical exponent agree with the values predicted by scaling theory. The 2D regime coexistence curve amplitude dependence upon film thickness is consistent with scaling theory. There exists an unanticipated interaction between the fluid films and the interferometer mirrors in contact with them. This is manifested in a uniform, film thickness dependent, displacement of the entire coexistence curve structure in temperature. We have completed construction of an ellipsometer to be used in studies of the interface between a solid surface and a critical fluid. In addition, we have assembled, and are currently evaluating, a system for studying the intensity autocorrelation of light scattered from critical fluid films. Progress has been made toward developing mathematical techniques for analyzing nonexponential correlation functions in terms of expansions in orthogonal polynomials.

• Research Organization: Colorado Univ., Boulder (USA)
• OSTI ID: 5755105
• Report Number(s): COO-2203-7-T1
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
654001 -- Radiation & Shielding Physics-- Radiation Physics
Shielding Calculations & Experiments
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
CRYSTAL MODELS
ELECTROMAGNETIC RADIATION
FILMS
HYDROGEN COMPOUNDS
ISING MODEL
LASER RADIATION
MATHEMATICAL MODELS
NEUTRAL-PARTICLE TRANSPORT
OXYGEN COMPOUNDS
PHOTON TRANSPORT
RADIATION TRANSPORT
RADIATIONS
SCATTERING
WATER