1. Othmer Department of Chemical & Biological Sciences & Engineering, Polytechnic University, Brooklyn, New York 11201; Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Physics, Yale University, New Haven, Connecticut 06520; Argonne National Laboratory, Argonne, Illinois 60439; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720