[1] Univ Tubingen, Inst Kristallog, D-72070 Tubingen, Germany
[2] Univ Zurich, Inst Inorgan Chem, CH-8057 Zurich, Switzerland
[3] JASCO Int Co Ltd, Hachioji, Tokyo 193, Japan
[4] Univ Hamburg, D-20146 Hamburg, Germany
[5] Univ Augsburg, EKM, Inst Phys, D-86135 Augsburg, Germany
[6] IBM Corp, Div Res, Zurich Res Lab, CH-8803 Ruschlikon, Switzerland
[7] ETH Honggerberg, Inst Quantenelekt, CH-8093 Zurich, Switzerland
[8] So Oregon Univ, Dept Phys, Ashland, OR 97520 USA