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Updated: Oct 2, 2025

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Mutual Information in Conjugate Spaces for Neutral Atoms and Ions
Juan Carlos Angulo1,2, Sheila López-Rosa2,3
1Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, 18010 Granada, Spain.
Abstract:
The discrepancy among one-electron and two-electron densities for diverse N-electron atomss, enclosing neutral systems (with nuclear charge Z=N) and charge-one ions (|N-Z|=1), is quantified by means of mutual information, I, and Quantum Similarity Index, QSI, in the conjugate spaces position/momentum. These differences can be interpreted as a measure of the electron correlation of the system. The analysis is carried out by considering systems with a nuclear charge up to Z=103 and singly charged ions (cations and anions) as far as N=54. The interelectronic correlation, for any given system, is quantified through the comparison of its double-variable electron pair density and the product of the respective one-particle densities. An in-depth study along the Periodic Table reveals the importance, far beyond the weight of the systems considered, of their shell structure.
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