Lifetimes and decay mechanisms of isotopically substituted ozone above the dissociation threshold: matching quantum and classical dynamics

Abstract

Energies and lifetimes of vibrational resonances were computed for ¹⁸O-enriched isotopologue ⁵⁰O₃ = {¹⁶O¹⁶O¹⁸O and ¹⁶O¹⁸O¹⁶O} of the ozone molecule using hyperspherical coordinates and the method of complex absorbing potential. Various types of scattering resonances were identified, including roaming OO–O rotational states, the series corresponding to continuation of bound vibrational resonances of highly excited bending or symmetric stretching vibrational modes. Such a series become metastable above the dissociation limit. The coupling between the vibrationally excited O₂ fragment and rotational roaming gives rise to Feshbach type resonances in ozone. Different paths for the formation and decay of symmetric ¹⁶O¹⁸O¹⁶O and asymmetric species ¹⁶O¹⁶O¹⁸O were also identified. The symmetry properties of the total rovibronic wave functions of the ¹⁸O-enriched isotopologues are discussed in the context of allowed dissociation channels.