1. Department of Chemical Engineering Sichuan University Chengdu 610065 P. R. China
2. Physical and Computational Sciences Directorate Pacific Northwest National Laboratory Richland WA 99352 USA
3. ICGM Univ. Montpellier CNRS ENSCM Montpellier France
4. Energy and Environment Directorate Pacific Northwest National Laboratory Richland WA 99352 USA
5. Center for Neutron Diffraction National Institute of Standards and Technology Gaithersburg MD 20899 USA
6. Department of Chemistry University of North Texas Denton TX 76201 USA