Interatomic Repulsion and the Pauli Principle

Autor/in	McMillin, David R.
Titel	Interatomic Repulsion and the Pauli Principle
Quelle	In: Journal of Chemical Education, 98 (2021) 9, S.2912-2918 (7 Seiten)Infoseite zur Zeitschrift PDF als Volltext Verfügbarkeit
Zusatzinformation	ORCID (McMillin, David R.)
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0021-9584
DOI	10.1021/acs.jchemed.1c00326
Schlagwörter	Nuclear Physics; Molecular Structure; Chemistry; Scientific Concepts; Scientific Principles; Interaction + Suchen Sie Ihr Suchwort? Atomphysik; Kernphysik; Chemie; Interaktion
Abstract	Atoms may repel or attract each other, but bound systems get virtually all of the attention in the classroom. To address the imbalance, instructors can explore the basis of repulsion in a few simple systems and highlight the important role played by the Pauli principle. A good example is the first triplet excited state of H[subscript 2] wherein both electrons have the same spin. In light of the Hellmann-Feynman theorem, the net interaction is repulsive due to the low electron density that results in the region between the two nuclei. Analogous destabilization occurs in s-bonding systems involving 3 electrons because two-thirds of the electrons have the same spin. Symmetrical systems like He[subscript 2][superscript +] are exceptions and actually do form bonds because the minority spin is able to delocalize over both centers. In contrast, the ground state of the neutral He[subscript 2] system entails 2 [alpha] and 2 [beta] electrons and is strictly repulsive. Finally, the lowest energy triplet state of ethylene twists toward a D[subscript 2d] structure to avoid a destabilizing interaction akin to that identified in the triplet state of H[subscript 2]. (As Provided).
Anmerkungen	Division of Chemical Education, Inc. and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2022/1/01