title: Experimental evidence for crossover to mean-field tricritical behavior in a concentrated salt solution
abstract: We have discovered a mean-field multicritical point on the critical locus in an aqueous solution of 3-methylpyridine and sodium bromide. Light-scattering measurements indicate Ising-like asymptotic critical behavior at the lower salt concentrations. However, the temperature range of Ising critical behavior shrinks with increasing salt concentration and the critical behavior becomes mean-field-like at a concentration of about 17% mass fraction of NaBr. Emergence of a new characteristic length scale diverging at this point and a simultaneous pronounced increase in the background scattering suggests mean-field tricritical behavior associated with the formation of a microheterogeneous phase due to clustering of ions and molecules.
authors.affiliation: Institute for Physical Science and Technology and Department of Chemical Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.initials: MA
authors.lastname: Anisimov
authors.initials: J
authors.lastname: Jacob
authors.initials: A
authors.lastname: Kumar
authors.initials: VA
authors.lastname: Agayan
authors.initials: JV
authors.lastname: Sengers