Document Type
Article
Original Publication Date
2011
Journal/Book/Conference Title
Physical Review B
Volume
84
Issue
7
DOI of Original Publication
10.1103/PhysRevB.84.075435
Date of Submission
April 2015
Abstract
Metallic clusters containing 2, 8, 18, and 20 electrons are now known to exhibit enhanced stability that can be reconciled because of filled 1S, 1P, 1D, and 2S electronic shells within a simplified confined nearly free electron (NFE) gas. Here, we present first-principles studies on three isovalent clusters, i.e., ZnMg8, CuMg8−, and AuMg8−, each with 18 valence electrons. All the clusters exhibit local energetic stability but with differing origins. Although the stability of ZnMg8 can be reconciled within the conventional confined NFE picture with filled 1S2, 1P6, and 1D10shells, CuMg8− and AuMg8− are shown to be stable despite the unfilled D-shell. Their stability can be understood as a crystal field–like splitting of the otherwise degenerate D-shell because of internal electric fields of the positive ion cores that lead to a filled 1S2, 1P6, 1D8, 2S2 sequence separated by unfilled D2 states that form a large gap. We also examine the progression toward the metallic character in ZnMgn clusters, because isolated Mg and Zn atoms have filled valence 4s2 and 3s2 atomic states. As Mg atoms are added to a Zn atom, the excited atomic p-states in the Mg atoms hybridize rapidly with Zn and Mg s-states to promote a metallic character that evolves more rapidly than in pure Mgn clusters.
Rights
Medel, V.M., Reveles, J.U., Reber, A.C., et al. Closed-shell to split-shell stability of isovalent clusters. Physical Review B, 84, 075435 (2011). Copyright © 2011 American Physical Society.
Is Part Of
VCU Physics Publications
Comments
Originally published by the American Physical Society at: http://dx.doi.org/10.1103/PhysRevB.84.075435