TC11 15min11:28
AB INITIO VIBRATIONAL SPLITTINGS FOR HYDROGEN ATOM TRANSFER IN HO2-/O2H- ISOMERIZATION.

WAI-TO CHAN AND IAN P. HAMILTON, Department of Chemistry, Wilfrid Laurier University, Waterloo, Ontario.

A potential energy surface covering the interconversion between the two symmetry-equivalent geometries of the hydroperoxyl anion, HO2- via a symmetric T-shaped saddle point was computed at the QCISD(T)/6-311++G(2df,pd) level of theory. An analytical molecular potential function was fit to the \sl ab initio data. The classical barrier to the interconversion was estimated to be 6057 cm-1 Using the parameterized function the vibrational states were calculated by the discrete variable representation-distributed Gaussian basis method. Computations predict the onset of tunnelling from about 4 quanta in the bending mode-A splitting of 6 cm-1 is observed between the odd and even 040 state. Presence of at least one quanta in the O--O stretching mode enhances splitting significantly.