1. Center for Biomolecular Science and Engineering, Code 6950, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington DC, 20375, Laboratory for the Structure of Matter, Code 6030, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington DC 20375, and Department of Chemistry, The George Washington University, 725 21st Street NW, Washington DC 20052tls@cbmse.nrl.navy.mil