1. Air Force Research Laboratory, Space Vehicles Directorate, 29 Randolph Road, Hanscom Air Force Base, Massachusetts 01731-3010, Institute for Scientific Research, Boston College, Chestnut Hill, Massachusetts 02467, The Open University of Israel, 108 Ravutski Street, Raanana, Israel, 43107, Physical Sciences Inc., 20 New England Business Center, Andover Massachusetts 01810, and Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520-8107