1. Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, MC 128-95, Pasadena, California 91125, United States
2. Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-Ro,
Yuseong-Gu, Daejeon 34141, Korea
3. Computational Science & Engineering Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States