Low-temperature kinetics for the N + NO reaction: experiment guides the way

Koner, Debasish (2023) Low-temperature kinetics for the N + NO reaction: experiment guides the way. Physical Chemistry Chemical Physics, 25 (20). pp. 13854-13863. ISSN 1463-9076

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Abstract

The reaction N(4S) + NO(X2Π) → O(3P) + N2(X1Σ+g) plays a pivotal role in the conversion of atomic to molecular nitrogen in dense interstellar clouds and in the atmosphere. Here we report a joint experimental and computational investigation of the N + NO reaction with the aim of providing improved constraints on its low temperature reactivity. Thermal rates were measured over the 50 to 296 K range in a continuous supersonic flow reactor coupled with pulsed laser photolysis and laser induced fluorescence for the production and detection of N(4S) atoms, respectively. With decreasing temperature, the experimentally measured reaction rate was found to monotonously increase up to a value of (6.6 ± 1.3) × 10−11 cm3 s−1 at 50 K. To confirm this finding, quasi-classical trajectory simulations were carried out on a previously validated, full-dimensional potential energy surface (PES). However, around 50 K the computed rates decreased which required re-evaluation of the reactive PES in the long-range part due to a small spurious barrier with a height of ∼40 K in the entrance channel. By exploring different correction schemes the measured thermal rates can be adequately reproduced, displaying a clear negative temperature dependence over the entire temperature range. The possible astrochemical implications of an increased reaction rate at low temperature are also discussed.

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IITH Creators:

IITH Creators	ORCiD
Koner, Debasish	http://www.orcid.org/0000-0002-5116-4908

Item Type:

Article

Uncontrolled Keywords:

Reaction rates; Computational investigation; Experimental investigations; Flow reactors; Interstellar clouds; Low-temperature kinetics; Lows-temperatures; Molecular nitrogen; Potential-energy surfaces; Reactions rates; Thermal; Atom lasers; Photolysis; Potential energy; Pulsed lasers; Quantum chemistry; Temperature distribution

Subjects:

Chemistry
Chemistry > Inorganic chemistry

Divisions:

Department of Chemistry

Depositing User:

Mr Nigam Prasad Bisoyi

Date Deposited:

28 Sep 2023 09:28

Last Modified:

28 Sep 2023 09:28

URI:

http://raiithold.iith.ac.in/id/eprint/11707