1. Department of Chemistry, Faculty of Science; Mahidol University; Rama VI Road, Ratchathewi Bangkok 10400 Thailand
2. Department of Chemistry, Physical and Theoretical Chemistry Laboratory; Oxford University; South Parks Road Oxford OX1 3QZ UK), Phone: +44(0) 1865 275957, Fax: +44 (0) 1865 275410
3. Department of Material; University of Oxford; OX1 3PH UK