VALENCE ISOMERIZATION OF IONIZED OXIRANE

The valence isomerization reactions of the cation radical of oxirane a re investigated using ab initio QCISD methods. There are two stable fo rms of the ion with the ring intact. The O ionized form is the ground state; a C-C ionized state lies 10.0 kJ/mol higher. The activation ene rgy for ring opening is 23.2 kJ/mol. The open form is planar, has C-2v , symmetry, and is 99.7 kJ/mol more stable than the pound state with t he ring intact. IRC calculations at the MP2 level follow the reaction from both the conrotatory and disrotatory transition states. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.