Potential energy surface of interaction of two diatomic molecules for air flows simulation

Abstract The dataset contains the potential energy surface (PES) of interaction of two diatomic molecules. Interaction between different pairs of nitrogen and oxygen molecules is considered: N2‒N2, N2‒O2, O2‒O2. The dependence of energy on the angles of mutual orientation of the two molecules are carefully described so that the obtained PES would be suitable for simulating the excitation and relaxation of rotational degrees of freedom in intermolecular collisions in air. For each pair of molecules more than 18000 quantum-mechanical DFT calculations were performed. A multi-particle interaction model was proposed to fit the DFT results with good accuracy. Corresponding force field and its software implementation are attached and one can use it for trajectory molecular dynamics (MD) calculations. Related Publication A detailed description of the data posted here will be presented in the paper: Artem Yakunchikov, Vasily Kosyanchuk, Alexander Kroupnov, Michael Pogosbekian, Ilya Bryukhanov, Aliya Iuldasheva, Potential energy surface of interaction of two diatomic molecules for air flows simulation at intermediate temperatures // Chemical Physics, 536:110850, 2020. https://doi.org/10.1016/j.chemphys.2020.110850 Model code (C++) The described models and force field computation were implemented as a C++ code: C++ class for obtained potential - airpotentials.h Example of use - airlib.cpp Before use, it is necessary to initialize the model from the file: // Model class airpotentials model; // Init model from file model.LoadModelFromFile(\"m1 - N2N2.txt\"); To calculate the energy and forces, it is necessary to call function ComputeEnergy(...) with the coordinates of the atoms and a pointer to the array into which the forces on the atoms will be stored: // Atoms coordinates and forces double x[4][3] = {...}; double f[4][3]; // Energy and forces computation double U = model.ComputeEnergy(x,&f[0][0]); Acknowledgments The research is carried out using the equipment of the shared research facilities of HPC computing resources at Lomonosov Moscow State University and Joint Supercomputer Center of the Russian Academy of Sciences. The research was supported by the Russian Foundation for Basic Research (project № 18-31-20025).