Mutual Information in Conjugate Spaces for Neutral Atoms and Ions Angulo Ibáñez, Juan Carlos López Rosa, Sheila Mutual information Quantum similarity index Electron correlation Multielectronic systems Author Contributions: Both authors have contributed equally to the planning and development of this research. All authors have read and agreed to the published version of the manuscript Funding: This work was supported by the Spanish grants PID2020-113390GB-I00 (funded by MCIN/AEI/10.13039/501100011033), PY20 00082 (Junta de Andalucía) and A-FQM-52-UGR20 (ERDF-University of Granada), and the Andalusian research groups FQM-4643, FQM-7276, FQM-207 and FQM-239. 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. 2022-02-16T12:24:25Z 2022-02-16T12:24:25Z 2022-02-02 journal article Angulo, J.C.; López-Rosa, S. Mutual Information in Conjugate Spaces for Neutral Atoms and Ions. Entropy 2022, 24, 233. [https://doi.org/10.3390/e24020233] http://hdl.handle.net/10481/72872 10.3390/e24020233 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España MDPI