1. Arthur Amos Noyes Laboratory of Chemical Physics, MC 127-72, California Institute of Technology, Pasadena, California 91125
2. NASA Jet Propulsion Laboratory, MC 183-901, California Institute of Technology, Pasadena, California 91109
3. Department of Chemistry, Washington State University, Pullman, Washington 99164-4630
4. Department of Chemistry, Purdue University, West Lafayette, Indiana 47907A