title: Ab initio state-specific N2+ O dissociation and exchange modeling for molecular simulations.
abstract: Quasi-classical trajectory (QCT) calculations are used in this work to calculate state-specific N2(X1Σ)+O(3P)→2N(4S)+O(3P) dissociation and N2(X1Σ)+O(3P)→NO(X2Π)+N(4S) exchange cross sections and rates based on the 13A″ and 13A' ab initio potential energy surface by Gamallo et al. [J. Chem. Phys. 119, 2545-2556 (2003)]. The calculations consider translational energies up to 23 eV and temperatures between 1000 K and 20 000 K. Vibrational favoring is observed for dissociation reaction at the whole range of collision energies and for exchange reaction around the dissociation limit. For the same collision energy, cross sections for v = 30 are 4 to 6 times larger than those for the ground state. The exchange reaction has an effective activation energy that is dependent on the initial rovibrational level, which is different from dissociation reaction. In addition, the exchange cross sections have a maximum when the total collision energy (TCE) approaches dissociation energy. The calculations are used to generate compact QCT-derived state-specific dissociation (QCT-SSD) and QCT-derived state-specific exchange (QCT-SSE) models, which describe over 1 × 106cross sections with about 150 model parameters. The models can be used directly within direct simulation Monte Carlo and computational fluid dynamics simulations. Rate constants predicted by the new models are compared to the experimental measurements, direct QCT calculations and predictions by other models that include: TCE model, Bose-Candler QCT-based exchange model, Macheret-Fridman dissociation model, Macheret's exchange model, and Park's two-temperature model. The new models match QCT-calculated and experimental rates within 30% under nonequilibrium conditions while other models under predict by over an order of magnitude under vibrationally-cold conditions.
authors.affiliation: Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Han
authors.identifier: 000000015013147X
authors.initials: H
authors.lastname: Luo
authors.affiliation: Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Marat
authors.initials: M
authors.lastname: Kulakhmetov
authors.affiliation: Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Alina
authors.identifier: 0000000321239064
authors.initials: A
authors.lastname: Alexeenko