1. Institute of Theoretical Chemistry and Computational Materials Science, China University of Geosciences, Wuhan 430074, China, Department of Physics, Penn State University, Berks Campus, Reading, Pennsylvania 19610-6009, Department of Microengineering, Kyoto University, Kyoto 606-8501, Japan, and Air Products and Chemicals, Incorporated, 7201 Hamilton Boulevard, Allentown, Pennsylvania 18195-1501