ISSN:
1432-2234
Keywords:
Key words: Quantum similarity
;
Similarity measures and indices
;
One-electron density
;
Intracule and extracule densities
;
Molecular alignment
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract. The calculation of quantum similarity measures from second-order density functions contracted to intracule and extracule densities obtained at the Hartree-Fock level is presented and applied to a series of atoms, (He, Li, Be, and Ne), isoelectronic molecules (C2H2, HCN, CNH, CO, and N2), and model hydrogen-transfer processes (H2/H+, H2/Hot, H2/H−). Second-order quantum similarity measures and indices are found to be suitable measures for quantitatively analyzing electron-pair density reorganizations in atoms, molecules, and chemical processes. For the molecular series, a comparative analysis between the topology of pairwise similarity functions as computed from one-electron, intracule, and extracule densities is carried out and the assignment of each particular local similarity maximum to a molecular alignment discussed. In the comparative study of the three hydrogen-transfer reactions considered, second-order quantum similarity indices are found to be more sensitive than first-order indices for analyzing the electron-density reorganization between the reactant complex and the transition state, thus providing additional insights for a better understanding of the mechanistic aspects of each process.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002140050301
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