[1] Beijing Computat Sci Res Ctr, Beijing 100084, Peoples R China
[2] Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA
[3] Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA
[4] Iowa State Univ, Dept Chem, US DOE, Ames Lab, Ames, IA 50011 USA
[5] Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA