From chemistry-request@server.ccl.net Thu Jun 24 17:19:45 1999 Received: from alchemy.chem.utoronto.ca (alchemy.chem.utoronto.ca [142.150.224.224]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id RAA31217 for ; Thu, 24 Jun 1999 17:19:45 -0400 Received: (from elewars@localhost) by alchemy.chem.utoronto.ca (8.9.3/8.9.3) id RAA27841 for chemistry@ccl.net; Thu, 24 Jun 1999 17:16:00 -0400 (EDT) Date: Thu, 24 Jun 1999 17:16:00 -0400 (EDT) From: "E. Lewars" Message-Id: <199906242116.RAA27841@alchemy.chem.utoronto.ca> To: chemistry@ccl.net Subject: CALC ACTIVATION E AND STABILITY 1999 June 24 Hello, Does anyone know have some *experimental facts* for the relationship between ab initio (or DFT, or semiempirical) calculated activation enewrgies and stability? I mean simply the transition state energy minus the reactant energy, for formally unimolecular reactions, e.g. isomerizations, or decompositions. How high does the calculated barrier have to be for the compound to be isolable at room temperature, for example, from actual experience in the lab? Thanks E. Lewars ======================