Average Time-Delays for the Scattering of O Atoms from O₂ Molecules

We report full quantum-computed average microcanonical, initial state-specific, and canonical cumulative time-delays associated with the O + O₂ scattering, presented as a function of total energy (in relation to an idealized molecular beam experiment) or temperature (for the properties of the gas phase in bulk conditions). We show that these quantities are well-defined and computable, with a temperature-dependent (canonical) time-delay presenting a smooth, monotonic decreasing behavior with temperature, despite an energy-dependent (microcanonical) time-delay of apparent chaotic character. We discuss differences in behavior when considering isotopic variations, ¹⁸O + ¹⁶O¹⁶O and ¹⁶O + ¹⁶O¹⁸O, with respect to the reference process ¹⁶O + ¹⁶O¹⁶O and reveal a greater magnitude of the cumulative time-delay when genuinely reactive events can take place, in the presence of ¹⁸O. These results constitute an addition to more conventional fashions (like cross sections and rate constants) of displaying information related to collisions in various experimental contexts.