Collect. Czech. Chem. Commun. 1988, 53, 2239-2249

Effect of electron correlation on SN2 activation barriers. Fourth-order MBPT calculations

Ivan Černušák and Miroslav Urban

Department of Physical Chemistry, Comenius University, Mlynská Dolina CH-1, CS-842 15 Bratislava


The activation barriers for a series of model gas-phase nucleophilic displacement reactions have been calculated at the MBPT(4)/DZ + P + D level. Electron correlation significantly reduces the barrier height, in most cases by about 50%. The role of individual contributions up to the fourth order MBPT is analyzed in detail showing the vital importance of single and triple excitations.