Experimental evidence for crossover to mean-field tricritical behavior in a concentrated salt solution
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.
Anisimov
MA
Institute for Physical Science and Technology and Department of Chemical Engineering, University of Maryland, College Park, Maryland 20742, USA.
Jacob
J
Kumar
A
Agayan
VA
Sengers
JV