1. Institute of Physical and Theoretical Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt/M, Germany; Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44, 01-224 Warsaw, Poland; Department of Chemistry, Technical University of Kaiserslautern, Erwin-Schrödinger-Str. 52, 67663 Kaiserslautern, Germany; and Department of Chemistry, University of Houston, Houston, Texas 77204-5003