1. Department of Chemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 866-8555, Japan
2. Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
3. Department of Physics, Nara Women's University, Kitauoyanishi-machi, Nara 630-8506, Japan