1. Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Department of Physics, Faculty of Science, Mahidol University, Rama 6 Rd., Bangkok 10400, Thailand, Department of Physics, Tunghai University, Taichung 407, Taiwan,Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan, Molecular Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei 115, Taiwan, Center for Condensed Matter Sciences, National...