How multivalency controls ionic criticality.
To understand how multivalency affects criticality in z:1 ionic fluids, we report an ion-cluster association theory embodying ionic solvation and excluded volume for equisized hard-sphere models with z=1-3. In accord with simulation but contradicting integral equation and field theories, the reduced critical temperature falls when z increases while the density rho(c) rises steeply. These trends can be explained semiquantitatively by noting that 80%-90% of the ions near T(c) are bound in neutral or charged clusters, depleting the ionic strength. For z not equal 1, predicted interphase Galvani potentials vanish at T(c).
Fisher
Michael E
ME
Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA.
Aqua
Jean-Noël
JN
Banerjee
Shubho
S