8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Tue 611:23-14:00P2.9Ionic dissociation revisitedAndy Ballard 11 University of Maryland, 2228 Chemistry Building, 20742, College Park, MD,United States of AmericaIt is known that the dissociation of Na-Cl in water is influenced by the structure of the surroundingsolvent molecules. We revisit this problem, with the goal of finding a reaction coordinate thataccurately captures the dissociation event. By applying committor analysis to configurations withselectively frozen-out solvent degrees of freedom, we are able to determine collective variables ofthe system that are important for the reaction to proceed. Our computational studies reveal thatthese variables must include information from a) water molecules as far away as the third solvationshell, and b) orientations of the individual water molecules. We also investigate the thermodynamicsof the reaction, finding that ionic dissociation is favored energetically and opposed entropically.9