Ab initio and DFT study of the ground (3)A ' potential energy surface for the O(P-3)+N2O -> 2NO reaction

An ab initio CASPT2//CASSCF and a DFT B3LYP study of the ground (3)A ' pote ntial energy surface (PES) for the title reaction have been carried out. Tw o reaction paths with cis- and trans- arrangements are described. Surface c rossings are noted in both paths, while bifurcative behaviour is present in the energetically favoured cis-path. These phenomena have been analysed in more detail at the DFT level. The rate constant values have been calculate d by means of the conventional transition state theory, including the contr ibution from the ground (3)A " PES (reported elsewhere), yielding very good accordance with the experiment in the case of the CASPT2//CASSCF method. ( C) 2001 Elsevier Science B.V. All rights reserved.