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Published March 8, 2001 | public
Journal Article

NO_2 Quantum Yield from the 248 nm Photodissociation of Peroxynitric Acid (HO_2NO_2)

Abstract

Peroxynitric acid (PNA) was photolyzed at 248 nm, and the NO_2 photoproduct was detected by laser-induced fluorescence (LIF). The quantum yield for the production of NO_2 was determined by comparison with HNO_3 photolysis data taken under identical experimental conditions. Measurements made over a range of pressures, flows, and precursor concentrations resulted in an NO_2 quantum yield of 0.56 ± 0.17, where the statistical uncertainty is 2 standard deviations. Calculations of potential energy curves for several low-lying singlet and triplet states of PNA are presented. The calculations show that while the singlet excitations occur via an n−π* transition on the NO_2 moiety, the dissociative channels forming OH + NO_3 and HO_2 + NO_2 likely occur via predissocation on different surfaces. Excitation energies at the MRCI and CCSD(T) level of theory show that excited states of PNA are not accessible at wavelengths longer than 407 nm (∼3.0 eV).

Additional Information

© 2001 American Chemical Society. Received: May 31, 2000; In Final Form: October 31, 2000. Publication Date (Web): December 22, 2000. We acknowledge the technical support of Mr. Dave Natzic. The supercomputer used in this investigation was provided by funding from the NASA Offices of Earth Science, Aeronautics and Space Science. The research was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Support from the NASA Upper Atmosphere Research, Tropospheric Chemistry and Atmospheric Effects of Aircraft Programs is acknowledged.

Additional details

Created:
August 19, 2023
Modified:
October 25, 2023