Photodissociation Dynamics of Reactive Radicals

Photodissociation dynamics of reactive radicals explores how the absorption of photons induces bond rupture in transient molecular species, leading to fragment products with well‐defined energy and angular distributions. These processes underpin chemistry in the upper atmosphere, planetary environments and combustion systems, where radicals such as CH₂Cl, CH₂Br and C₂H₅ play a pivotal role in ozone depletion, pollutant formation and fuel oxidation. Experimentally, time‐resolved spectroscopic methods—ranging from ultrafast lasers and free‐electron‐laser sources to velocity‐map imaging—capture the partitioning of translational, rotational and vibrational energy in nascent fragments. Theoretically, multireference configuration‐interaction calculations, quasiclassical trajectory simulations and non‐adiabatic coupling analyses on high‐accuracy potential energy surfaces unravel the influence of conical intersections, spin–orbit coupling and predissociation pathways. Together, these approaches reveal how initial excitation wavelength, angular momentum and ro‐vibrational state govern dissociation mechanisms, offering predictive insight for atmospheric modelling, astrochemical interpretation and the design of combustion processes with reduced pollutant output.

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Photodissociation Dynamics of Reactive Radicals publication trend

The graph below shows the total number of articles in photodissociation dynamics of reactive radicals across all publications each year (not limited to Nature Index journals).

Technical terms

Photodissociation dynamics: Study of how photon absorption leads to molecular bond cleavage and fragment formation.

Reactive radical: A short-lived molecular fragment with one or more unpaired electrons that drives subsequent chemical reactions.

Potential energy surface (PES): A multidimensional surface describing the electronic energy of a molecule as a function of nuclear coordinates.

Non-adiabatic coupling: Interaction between electronic states enabling transitions at points such as conical intersections.

Conical intersection: A region where two potential energy surfaces of the same symmetry intersect, facilitating ultrafast electronic transitions.

Spin–orbit coupling: Interaction between an electron’s spin and its orbital motion, affecting energy levels and dissociation pathways.

References

1. Site-specific hydrogen-atom elimination in photoexcited ethyl radical. Chemical Science (2019).
2. Photodissociation of the CH2Cl radical: A high-level ab initio study. The Journal of Chemical Physics (2024).
3. Photodissociation of the CH2Br radical: A theoretical study. The Journal of Chemical Physics (2024).