Information-Theoretic Approaches in Molecular Reactivity

Information-theoretic approaches apply measures derived from probability and density distributions to characterise and predict chemical reactivity. By treating the electron density as a probability field, metrics such as Shannon entropy and Fisher information quantify the delocalisation and localisation of electrons, respectively. These descriptors complement conventional energy‐based methods, offering insights into bond formation, transition‐state structure and reaction pathways without explicit reliance on wavefunction complexity. Recent developments have extended these tools to three‐dimensional hypersurfaces of reactivity, to excited states, and to large biopolymers, enabling more accurate mapping of reactive regions, assessment of molecular polarizabilities and dissection of energetic contributions. This fusion of information theory with density functional frameworks promises enhanced predictive power in areas from catalysis and materials design to photochemical processes.

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Information-Theoretic Approaches in Molecular Reactivity publication trend

The graph below shows the total number of articles in information-theoretic approaches in molecular reactivity across all publications each year (not limited to Nature Index journals).

Technical terms

Information-Theoretic Approach: A methodology that uses information measures derived from electron density and its gradients to analyse molecular structure and reactivity.

Shannon entropy: A measure of the spread or delocalisation of the electron density distribution, reflecting the degree of disorder in the electronic cloud.

Fisher information: A measure of the localised fluctuations or gradients in the electron density, indicating the sharpness of electronic features and reactive sites.

Density Functional Theory (DFT): A quantum‐mechanical method that employs the electron density as the primary variable to compute molecular energies, structures and properties.

Fisher-Shannon complexity: A combined metric that captures both the extent of delocalisation (through entropy) and localisation (through Fisher information) in a single descriptor of molecular electronic structure.

References

1. Density-based Reactivity Theory Applied to Excited States. AAPPS Bulletin (2024).
2. A Density Functional Theory and Information-Theoretic Approach Study of Interaction Energy and Polarizability for Base Pairs and Peptides. Pharmaceuticals (2022).
3. 3D Information-Theoretic Analysis of the Simplest Hydrogen Abstraction Reaction. The Journal of Physical Chemistry A (2023).