Related Experiment Video
Updated: Jun 8, 2026
05:51
Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
Quantum dynamics of the S+OH→SO+H reaction
Mohamed Jorfi1, Pascal Honvault
1Institut UTINAM, UMR CNRS 6213, University of Franche-Comté, 25030 Besançon cedex, France.
The Journal of Chemical Physics
|October 19, 2010
Summary
Accurate quantum calculations reveal reaction dynamics for S + OH. Rate constants were determined, showing mixed direct and indirect reaction mechanisms.
Area of Science:
- Chemical Kinetics
- Quantum Mechanics
- Atmospheric Chemistry
Background:
- The reaction between sulfur monoxide (SO) and hydroxyl radical (OH) is significant in atmospheric chemistry.
- Understanding the reaction mechanism is crucial for atmospheric modeling.
Purpose of the Study:
- To perform the first accurate quantum mechanical scattering calculations for the S + OH reaction.
- To determine reaction probabilities and calculate rate constants over a relevant temperature range.
Main Methods:
- Ab initio potential energy surface calculations for the HSO ground electronic state.
- Quantum mechanical scattering calculations for total angular momentum J=0.
- J-shifting approach for rate constant calculation.
Main Results:
- Total and state-to-state reaction probabilities were computed up to 0.5 eV collision energy.
- Rate constants were calculated for the 10-400 K temperature range.
- Product vibrational and rotational distributions indicated a mix of direct and indirect reaction pathways.
Conclusions:
- The study provides accurate theoretical insights into the S + OH reaction dynamics.
- The findings contribute to a better understanding of sulfur chemistry in atmospheric environments.
- The reaction mechanism is characterized as a combination of direct and indirect processes.
Related Concept Videos
03:25Free Energy Changes for Nonstandard States
The free energy change for a process taking place with reactants and products present under nonstandard conditions (pressures other than 1 bar; concentrations other than 1 M) is related to the standard free energy change according to this equation:
01:26Reaction Mechanisms: The Steady-State Approximation
The steady-state approximation, also referred to as the quasi-steady-state approximation to differentiate it from a true steady state, is a widely used method for simplifying calculations in complex reaction mechanisms. This approach is particularly useful when dealing with multi-step reactions that involve reverse reactions or several steps, which can significantly increase mathematical complexity and make the reactions nearly unsolvable analytically.The steady-state approximation operates on...
03:40Hess's Law
There are two ways to determine the amount of heat involved in a chemical change: measure it experimentally, or calculate it from other experimentally determined enthalpy changes. Some reactions are difficult, if not impossible, to investigate and make accurate measurements for experimentally. And even when a reaction is not hard to perform or measure, it is convenient to be able to determine the heat involved in a reaction without having to perform an experiment.
03:51Molecular Orbital Theory II
Molecular Orbital Energy Diagrams
02:35Molecular Orbital Theory I
Overview of Molecular Orbital Theory
02:26SN2 Reaction: Transition State
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...