Exploring the possibility of a bimolecular reaction channel for the F2SS/FSSF rearrangement process

A theoretical study of the F2SS/FSSF isomerization is presented, where the possibility of a bimolecular reaction channel to occur is explored by intro ducing the effect of a second F2SS molecule on the unimolecular process. At the HF/6-31G* level of theory, three alternative bimolecular routes are id entified and the corresponding reactant and product complexes and transitio n states characterized. The most favourable bimolecular pathway is then ana lyzed at the HF, MP2, and B3P86 levels of theory using the 6-31+G* basis se t. Results including electron correlation effects give energy barriers for the bimolecular process only a few (3-5) kcal/mol below those encountered f or the unimolecular process. Consequently, the isomerization process is unl ikely to proceed via this bimolecular channel because the energy barrier is still too high (40.0 kcal/mol at the MP2/6-31+G* level). (C) 1998 Elsevier Science B.V. All rights reserved.