10.1021/jp5076059.s005 Ana Martín-Sómer Ana Martín-Sómer Manuel Yáñez Manuel Yáñez Marie-Pierre Gaigeot Marie-Pierre Gaigeot Riccardo Spezia Riccardo Spezia Unimolecular Fragmentation Induced By Low-Energy Collision: Statistically or Dynamically Driven? American Chemical Society 2014 simulation time length Unimolecular Fragmentation Induced energy distributions mechanism reactivity CID dynamics accounting Sr chemical dynamics simulations chemical dynamics simulations account IVR RRKM 2014-11-20 00:00:00 Media https://acs.figshare.com/articles/media/Unimolecular_Fragmentation_Induced_By_Low_Energy_Collision_Statistically_or_Dynamically_Driven_/2233504 By combining chemical dynamics simulations and RRKM statistical theory we have characterized collision induced dissociation (CID) mechanisms of [M­(formamide)]<sup>2+</sup> ions (M = Ca, Sr) at different timescales, from few femtoseconds to microseconds. Chemical dynamics simulations account for the short-time and dynamically driven reactivity, such as impulsive collision mechanism for formamide neutral loss. From the simulations, we also got the amounts of energy transferred during the collision and, especially important, the vibrational and rotational energy distributions of the ions that did not react during the simulation time length of 2.5 ps. These internal energy distributions were in turn used in combination with RRKM theory to estimate the rate constants of the possible reactive pathways. Hence, we performed a statistical analysis of the CID dynamics accounting for the long-time and statistical reactivity (i.e., through an IVR mechanism). This multiscale approach allowed us to account for all the products observed in the CID experimental spectra of [Ca­(formamide)]<sup>2+</sup> and [Sr­(formamide)]<sup>2+</sup> doubly charged cations, as well as the differences between them.