1. ICGM, ENSCM, CNRS Université Montpellier 34296 Montpellier France
2. PAC CNRS-UM-ENSCM ICGM Montpellier 34296 Montpellier France
3. Fluorine Division, Research & Development Center Mitsubishi Materials Electronic Chemicals Co, Ltd 3-1-6, Barajima Akita 010-8585 Japan