Affiliation: | a Department of Physics, Liaoning University, 66 Chong Shan Middle Road, Shenyang 110036, China b College of Mathematics and Physics, Jinggangshan University, Ji''an 343009, China c Key Laboratory of Excited State Processes, Chinese Academy of Sciences, Changchun 130033, China d Department of Physics, Georgia Southern University, Statesboro, GA 30460, USA |