1. Department of Chemistry, Columbia University, 3000 Broadway, MC 3167, New York, New York 10027; Department of Chemistry and Stanford Synchrotron Research Laboratory, Stanford University, Stanford, California 94305-5080; Department of Chemistry, Clemson University, Clemson, South Carolina 29634; Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000; IBM T. J. Watson Research Center, Yorktown Heights, New York 10598; Radiation Laboratory, University of Notre Dame, Notre Dame,...