Computational Chemical Kinetics and Reaction Mechanisms

Computational chemical kinetics and reaction mechanisms integrate quantum chemistry, statistical rate theories and kinetic modelling to reveal the fundamental pathways and rates of chemical processes. By mapping potential energy surfaces, locating transition states and evaluating molecular dynamics, these approaches enable the prediction of reaction rate constants under varying temperatures and pressures. Key components include variational transition state theory, master equation solvers for pressure-dependent kinetics and explicit treatment of quantum phenomena such as tunnelling and anharmonicity. Such methods underpin the development of refined atmospheric and combustion models, materials synthesis pathways and catalytic systems, offering a predictive framework that bridges microscopic mechanism elucidation with macroscopic observables. Advances in computational power and algorithmic efficiency have extended these techniques to large molecular systems and complex reaction networks, providing comprehensive insights into radical chemistry, isomerisation processes and multistep catalytic cycles, thereby shaping modern chemical science and engineering.

Research from Nature Portfolio

Recent studies have elucidated the oxidation mechanism of methyl mercaptan by hydroxyl radicals across a wide range of temperatures and pressures. By constructing detailed potential energy surfaces using high-level electronic structure methods and evaluating fourteen possible reaction pathways, researchers have determined that hydrogen abstraction from the thiol group predominates under most atmospheric and combustion conditions. Pressure-dependent rate constants were computed to demonstrate how channel contributions shift with temperature, revealing the critical role of pre-reaction complex formation and high-precision methodologies in matching experimental kinetics and thermochemistry. These findings refine mechanistic descriptions of acid-rain precursor chemistry.

Computational Chemical Kinetics and Reaction Mechanisms publication trend

The graph below shows the total number of articles in computational chemical kinetics and reaction mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Potential energy surface (PES): A mathematical representation of the energy landscape of a molecular system as a function of nuclear coordinates.

Variational transition state theory (VTST): A method that locates the optimal dividing surface along a reaction coordinate to compute rate constants by minimising the free-energy barrier.

Tunnelling: A quantum mechanical effect allowing particles to traverse energetic barriers lower than their classical energy, significantly affecting reaction rates especially at low temperature.

Anharmonicity: Deviation from the harmonic oscillator model in molecular vibrations, which alters partition functions and reaction kinetics at elevated energies.

Master equation: A kinetic framework that resolves the population of chemical species over energy states to account for collisional energy transfer and pressure-dependent kinetics.

Multistructural effects: Contributions from multiple conformers and torsional states to the thermodynamic and kinetic properties of a reacting system.

References

1. Predicting pressure-dependent unimolecular rate constants using variational transition state theory with multidimensional tunneling combined with system-specific quantum RRK theory: a definitive test for fluoroform dissociation. Physical Chemistry Chemical Physics (2016).
2. Kinetics of the Toluene Reaction with OH Radical. Research (2019).
3. A Combined Systematic-Stochastic Algorithm for the Conformational Search in Flexible Acyclic Molecules. Frontiers in Chemistry (2020).