Pavel Jungwirth1, R. Benny Gerber. 1. J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague 8, Czech Republic, Department of Physical Chemistry and The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Department of Chemistry, University of California, Irvine, California 92697-2025.