1. Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269-3060, U-60, Charles E. Waring Laboratory, Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-4060, Department of Chemical Engineering, University of Connecticut, Storrs, Connecticut 06269-4060, and Molecular Simulations, Inc., 9685 Scranton Road, San Diego, California 92121-3752