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Alecu I, Gao Y, Marshall P. Experimental and Computational Studies of the Kinetics of the Reaction of Hydrogen Peroxide with the Amidogen Radical. J Chem Phys 2022; 157:014304. [DOI: 10.1063/5.0095618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The pulsed laser photolysis / laser-induced fluorescence method is used to study the kinetics of the reaction of NH2 with H2O2 to yield a second-order rate constant of (2.42 {plus minus} 0.55) × 10-14 cm3 molecule-1 s-1 at 412 K in 10-22 mbar Ar bath gas. There are no prior measurements for comparison. To check this value and to enable reliable extrapolation to other temperatures we also compute thermal rate constants for this process over the temperature range 180 - 3000 K via multi-structural canonical variational transition state theory with small-curvature multidimensional tunneling (MS-CVT/SCT). The CVT/SCT rate constants are derived using a dual-level direct dynamics approach utilizing single-point CCSD(T)-F12b/cc-pVQZ-F12 energies - corrected for core-valence and scalar relativistic effects - and M06-2X/MG3S geometries, gradients, and Hessians for all stationary and non-stationary points along the reaction path. The multi-structural method with torsional anharmonicity based on a coupled torsional potential (MS-T(C)) is then employed to calculate correction factors for the rate constants, accounting for the comprehensive effects of torsional anharmonicity on the kinetics of this reaction system. The final MS-CVT/SCT rate constants are found to be in good agreement with our measurements, and can be expressed in modified Arrhenius form as 2.13 × 10-15 ( T/298 K)4.02 exp(-513 K/ T) cm3 molecule-1 s-1 over the temperature range 298-3000 K.
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Affiliation(s)
- Ionut Alecu
- University of North Texas, United States of America
| | - Yide Gao
- University of North Texas, United States of America
| | - Paul Marshall
- Department of Chemistry, University of North Texas, United States of America
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