DETERGENT FOAM IMAGES AS ANALOGUE DIGITAL MODEL FLUIDS - 1 - PHASE-BEHAVIOR AND EFFECTIVE PAIR POTENTIALS/

Detergent foam images are investigated as analogue/digital (A/D) model s for simple fluids. Results of foam preparation/image processing expe riments with quasi-two-dimensional systems are illustrated. In the ana lysis, the pair and triplet correlation functions, g(r) and xi(Theta,s ;r), are measured for the vertexes of plateau border networks. The pha se morphology is characterized by the amplitude and extent of oscillat ions in g(r). Effective pair potentials u(r) are calculated via the lo west order equation in the Born-Yvon-Green hierarchy. The u(r) are fur ther investigated via Monte Carlo calculations and the Morse function. The experimental data are used to calculate the pair correlation entr opy and the compressibility factor as functions of particle number den sity. These and other observables enable comparisons between the model systems and real atomic fluids. Overall, the results show foam images to mimic fluid structure at the atomic level in several respects. For the experimental conditions discussed, successions of images offer no vel views of liquid-->gas transitions.