Computational study of collisions between O(P-3) and NO((2)Pi) at temperatures relevant to the hypersonic flight regime

Castro-Palacio, Juan Carlos and Nagy, Tibor and Bemish, Raymond J. and Meuwly, Markus. (2014) Computational study of collisions between O(P-3) and NO((2)Pi) at temperatures relevant to the hypersonic flight regime. Journal of Chemical Physics, 141 (16). p. 164319.

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Official URL: http://edoc.unibas.ch/dok/A6338876

Abstract

Reactions involving N and O atoms dominate the energetics of the reactive air flow around spacecraft when reentering the atmosphere in the hypersonic flight regime. For this reason, the thermal rate coefficients for reactive processes involving O(P-3) and NO((2)Pi) are relevant over a wide range of temperatures. For this purpose, a potential energy surface (PES) for the ground state of the NO2 molecule is constructed based on high-level ab initio calculations. These ab initio energies are represented using the reproducible kernel Hilbert space method and Legendre polynomials. The global PES of NO2 in the ground state is constructed by smoothly connecting the surfaces of the grids of various channels around the equilibrium NO2 geometry by a distance-dependent weighting function. The rate coefficients were calculated using Monte Carlo integration. The results indicate that at high temperatures only the lowest A-symmetry PES is relevant. At the highest temperatures investigated (20 000 K), the rate coefficient for the O1O2+N channel becomes comparable (to within a factor of around three) to the rate coefficient of the oxygen exchange reaction. A state resolved analysis shows that the smaller the vibrational quantum number of NO in the reactants, the higher the relative translational energy required to open it and conversely with higher vibrational quantum number, less translational energy is required. This is in accordance with Polanyi`s rules. However, the oxygen exchange channel (NO2+O1) is accessible at any collision energy. Finally, this work introduces an efficient computational protocol for the investigation of three-atom collisions in general. (C) 2014 AIP Publishing LLC.
Faculties and Departments: 05 Faculty of Science > Departement Chemie > Chemie > Physikalische Chemie (Meuwly) Meuwly, Markus Article, refereed Research Article American Institute of Physics 0021-9606 Publication type according to Uni Basel Research Database: Journal article -- The final publication is available at AIP, see DOI link. English doi: 10.1063/1.4897263isi: 000344589700048 07 Dec 2016 11:52 06 Feb 2015 09:59

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