High-Level Systematic ab Initio Comparison of Carbon- and Silicon-Centered SN2 Reactions Attila Á. Dékány, Gyula Z. Kovács, and Gábor Czakó* MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary * E-mail: gczako@chem.u-szeged.hu 4 SiH3- Si -0.0000520774 0.0780563560 0.0000040497 H -0.6845397541 -0.7252642140 -1.1188578297 H 1.3116655677 -0.7244008499 -0.0340323320 H -0.6256747144 -0.7253173611 1.1527773188