Carbon oxides in gas flows and earth and planetary atmospheres: State-to-state simulations of energy transfer and dissociation reactions

In this paper we illustrate an approach to the study of the molecular collision dynamics, suited for massive calculations of vibrational state-specific collision cross sections and rate constants of elementary gas phase processes involving carbon oxides. These data are used in the theoretical modeling of the Earth and planetary atmospheres and of non-equilibrium reactive gas flows containing the CO2 and CO molecules. The approach is based on classical trajectory simulations of the collision dynamics and on the bond-bond semi-empirical description of the intermolecular interaction potential, that allows the formulation of full dimension potential energy surfaces (the main input of simulations) for small and medium size systems. The bond-bond potential energy surfaces account for the dependence of the intermolecular interaction on some basic physical properties of the colliding partners, including modulations induced by the monomer deformation. The approach has been incorporated into a Grid empowered simulator able to handle the modeling of the CO2 + CO2 collisions, while extensions to other processes relevant for the modeling of gaseous flows and atmospheres, such as CO + CO → C + CO2 and CO2 + N2, are object of current work. Here the case of CO2 + CO2 collisions will be illustrated in detail to exemplify an application of the method. © 2013 Springer-Verlag Berlin Heidelberg.