1. Department of Chemistry, Faculty of Engineering Science Research Center for Photoenergetics of Organic Materials, Osaka University, Toyonaka, Osaka 560, Japan
2. Texas Instruments Tsukuba Research and Development Center Ltd., 17 Miyukigaoka, Tsukuba, Ibaraki 305, Japan
3. PRESTO, Research Development Corporation of Japan Department of Chemistry, Faculty of Engineering Science Research Center for Photoenergetics of Organic Materials, Osaka University, Toyonaka, Osaka 560, Japan