Collisional quenching of vibrationally excited O+2by Kr atoms is studied using timehyphen;dependent quantum mechanics with an emphasis on exploring the underlying mechanisms. Threehyphen;dimensional solutions to the timehyphen;dependent Schrouml;dinger equation with zero total angular momentum are obtained at two values of the average collision energy, 0.5 and 0.1 eV. At 0.5 eV, the 1rarr;0 quenching probability is computed to be 0.091. The rotational distributions of the vibrationally quenched O+2are highly bimodal. An analysis of lsquo;lsquo;nascentrsquo;rsquo;v=0 probability density reveals the origin of this bimodality and yields insight into the mechanisms of vibrational deexcitation. Comparisons are made to a corresponding classical study. Scattering at 0.1 eV is complicated by the existence of overlapping resonances in addition to the direct scattering. Due to these resonances, the quenching probability is an extremely sensitive function of energy. An averaged quenching probability of 0.078 at 0.1 eV is computed. Average resonance lifetimes of 2.5ndash;3.5 ps are also obtained from an analysis of the temporal behavior of the dissociating wave packet. The influence of the potential anisotropy on the quenching probabilities is discussed.
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