Nonadiabatic quantum dynamics calculations of transition state spectroscopy of I plus HI and I plus DI reactions: the existence of long life vibrational bonding resonances

We present the results of nonadiabatic quantum wave packet calculations to analyze the experimental transition state spectra for the I(P-2(3/2,1/2)) + XI (X = H and D) hydrogen exchange reactions based on photodetachment of the IXI- anion. We developed (3 x 3) diabatic potential energy surfaces that can reasonably describe the nonadiabatic transitions induced by spin-orbit interactions. A good agreement was obtained between theory and experiment and it was found that nonadiabatic transitions play a role in the reaction dynamics. We also found that the calculated spectra showed very sharp resonance states with a vibrational bonding character, where the resonance wavefunctions are highly localized around the transition state region. Our calculated results suggest that one may experimentally detect these vibrational bonding resonances using time-domain transition state spectroscopy techniques since those states have picosecond-order lifetimes.