Full six-dimensional nonadiabatic quantum dynamics calculation for the energy pooling reaction O-2(a(1)Delta)+O-2(a(1)Delta)-> O-2(b(1)Sigma)+O-2(X-3 Sigma)

Six new potential energy surfaces of four singlet states and two triplet states for the title oxygen molecule reaction along with the spin-orbit coupling among them have been constructed from the complete active space second-order perturbation theory with a 6-311+G(d) basis. Accurate integral cross sections are calculated with a full six-dimensional nonadiabatic time-dependent quantum wave packet method. The thermal rate constant based on the integral cross sections agrees well with the result of the experimental measurements, and the intersystem crossing effects are also discussed in this electronic energy-transfer process. (c) 2008 American Institute of Physics