1. Chair of Inorganic Chemistry, Ludwig-Maximilian University of Munich (LMU), Butenandtstrasse 5-13 (D), D-81377 Munich, Germany, Materials Dynamics (DX-2), Los Alamos National Laboratories, Los Alamos, New Mexico 87545, and Bundeswehr Research Institute for Materials, Fuels and Lubricants, Swisttal-Heimerzheim, Grosses Cent, D-53913 Swisttal, Germany