Chaohong Lee,* Wenhua Hai, Lei Shi, Xiwen Zhu, and Kelin Gao Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, Peoples Republic of China Department of Physics, Hunan Normal University, Changsha 410081, Peoples Republic of China ~Received 21 March 2001; revised manuscript received 4 June 2...
