Grid Calculation Tools for Massive Applications of Collision Dynamics Simulations: Carbon Dioxide Energy Transfer

The dynamics of CO2+CO2 collisions is a key issue in atmospheric chemistry, combustion, plasma and gas dynamics applications, one of the most relevant aspects being the energy transfer between translational, rotational and vibrational degrees of freedom. The use of collision observables such as cross sections and rates in kinetic models for practical applications is however conditioned to the availability of such quantities at a state-to-state level of accuracy. On the other hand, the accuracy is strongly dependent on the description of the intermolecular interactions in the CO2 dimer. Given the high number of quantum states for CO2 (with linear CO2 having four internal degrees of freedom) massive dynamics calculations are required to span the manifold of quantum states, a fact that restricts the alternatives to only quasiclassical trajectories, as the method to run dynamics. Due to the embarrassingly parallel nature of trajectories, such methods alongside a suitable choice of parallelization parameters (e. g. energy, angular momentum, etc..) greatly benefit of Grid computing environments. We present here some illustrative results obtained by quasiclassical trajectories (QCT) used in the framework of a recently developed theoretical and computational tool for collision simulations on the Grid, where the CO2-CO2 collisions are driven by a semiempirical intermolecular potential energy surface (PES) also recently developed.