Theoretical design of stable small aluminium-magnesium binary clusters

Edison Osorio, Alejandro Vasquez, Elizabeth Florez, Fanor Mondragon, Kelling J. Donald, William Tiznado

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

We explore in detail the potential energy surfaces of the Al xMgy (x, y = 1-4) systems as case studies to test the utility and limitations of simple rules based on electron counts and the phenomenological shell model (PSM) for bimetallic clusters. We find that it is feasible to design stable structures that are members of this set of small Al-Mg binary clusters, using simple electron count rules, including the classical 4n + 2 Hückel model, and the most recently proposed PSM. The thermodynamic stability of the title compounds has been evaluated using several different descriptors, including the fragmentation energies and the electronic structure of the systems. Three stable systems emerge from the analysis: the Al 4Mg, Al2Mg2 and Al4Mg4 clusters. The relative stability of Al4Mg is explained by the stability of the Al42- subunit to which the Mg atom donates its electrons. Here the Mg2+ sits above the aromatic 10 π-electron Al42- planar ring. The Al2Mg 2 and Al4Mg4 clusters present more complicated 3D structures, and their stabilities are rationalized as a consequence of their closed shell nature in the PSM, with 10 and 20 itinerant electrons, respectively.

Original languageEnglish
Pages (from-to)2222-2229
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume15
Issue number6
DOIs
Publication statusPublished - 14 Feb 2013

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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