Post-transition state chemical dynamics for gas phase reactivity of dications
Our aim is to understand reaction mechanisms that characterize reactivity of dications in the gas phase, in particular complexes formed by a divalent metal (Ca, Sr for example) and an organic molecule. Two general pathways are possible, Coulomb explosion and neutral loss and chemical dynamics simulations are performed to understand weather and when reactivity proceeds through a statistical or to a non-statistical mechanism, and how the metal affects the reactivity.
Post-transition state dynamics were able to explain the difference in reactivity found between the two systems, in particular the Sr2+ + formamide reaction channel was found to be much more probable than the analogous Ca2+ + formamide one when starting from a particular transition state. Another particular result was obtained by analyzing the reaction pathways dealing to [Ca(H2O)]2+ that proceeds to a different and fast pathway with respect to what obtained from PES study. This pathway was not observed for related Sr2+ system, confirming experimental results.
We are now planning to perform detailed analysis on wave-function character and bond character across the two reaction pathways to couple the dynamical differences with chemical differences. Furthermore, we decided to run a fourth (and probably last) set of chemical dynamics simulations from another transition state. Finally, we are setting up publications related to the project, and in particular thanks to the ad hoc analysis tools provided during the visit, we are rationalizing all post-transition state dynamics results to show how this approach can be complementary to the usual PES approach.