A new six-dimensional (6D) global potential energy surface (PES) is proposed for the full range description of the interaction of the N2(1Σg+)+N2(1Σg+) system governing collisional processes, including N atom exchange. The related potential energy values were determined using high-level ab initio methods. The calculations were performed at a coupled-cluster with single and double and perturbative triple excitations level of theory in order to have a first full range picture of the PES. Subsequently, in order to accurately describe the stretching of the bonds of the two interacting N2 molecules by releasing the constraints of being considered as rigid rotors, for the same molecular geometries higher level of theory multi reference calculations were performed. Out of the calculated values a 6D 4-atoms global PES was produced for use in dynamical calculations. The ab initio calculations were made possible by the combined use of High Throughput Computing and High Performance Computing techniques within the frame of a computing grid empowered molecular simulator.
Keywords: ab initio methods; dynamics; electronic structure calculation; fitting; potential energy surface.
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