VIBRATIONAL ENERGIES AND WAVE-FUNCTIONS OF HIGH-ENERGY LOCALIZED AND FLOPPY STATES OF NONROTATING HO2

I report vibrational energies of non-rotating H02 for even and odd parity states up to 17027 cm-1 using the dressed-state truncation/recoupling method [J.M. Bowman and B. Gazdy, J. Chem. Phys. 94 (1991) 454]. The potential surface used is the double many-body expansion one of Varandas and Brandao, for which the isomerization barrier height is 12039 cm-1. Based on the behavior of the odd-even energy splittings as a function of vibrational energy, evidence is presented that the ground state adiabatic barrier height is the meaningful quantity determining the threshold energy for isomerization. Localized states, i.e. those with very small splittings, are found at energies greatly in excess of the ground-state adiabatic barrier height.