1. Laboratory for
Chemical Physics,
Division of Basic Sciences, and Center for Skeletal Biology, New York University, 345 East 24th Street, New York, New York 10010, United States
2. Department
of Physics, University of York, Heslington, York YO10
5DD, U.K.
3. Department
of Chemistry, Physical Chemistry, Universität Konstanz, Universitätstrasse
10, D-78457 Konstanz, Germany