1. Institute of Crystallography, Russian Academy of Sciences; 119333 Moscow Russia
2. Institute of Optics and Atomic Physics, Technical University of Berlin; 10623 Berlin Germany
3. Department of Inorganic Chemistry, Faculty of Science; Charles University; 12840 Prague Czech Republic
4. Institute for Laser Science; University of Electro-Communications; Tokyo 182-8585 Japan
5. Section Crystallography; Institute of Geology and Mineralogy, University of Cologne; 50939 Cologne Germany