{
  "id": "1408.2715",
  "version": "v2",
  "published": "2014-08-12T14:09:16.000Z",
  "updated": "2015-03-05T15:11:26.000Z",
  "title": "Theoretical Study of the Stability of $\\mathrm{Au_nGe_{m}}$ Clusters",
  "authors": [
    "Danielle McDermott",
    "Kathie E. Newman"
  ],
  "comment": "19 pages, 16 figures + 7 supplemental figures",
  "doi": "10.1140/epjd/e2015-50607-910",
  "categories": [
    "cond-mat.mes-hall",
    "cond-mat.mtrl-sci",
    "physics.atm-clus"
  ],
  "abstract": "We investigate the properties of clusters formed from two connected $\\mathrm{Ge_{m}}$ cage-like clusters, such as experimentally synthesized $\\mathrm{Au_3Ge_{18}^{5-}}$, using first-principles DFT methods. We focus particularly on $\\mathrm{Au_nGe_{12}^{q-}}$ formed from $\\mathrm{Ge_{6}}$, where $n=0-3$ and $q=0,2$. We examine the geometries, electronic structure, and thermal excitations of these clusters using the SIESTA code, where we test stability using short molecular dynamics simulations. Our examination of intercluster bridges between $\\mathrm{Ge_{m}}$, formed of either Ge-Ge or Au-Ge bonds, indicates that the overlap of interacting molecular orbitals of $\\mathrm{Ge_{m}}$~can either bind a cluster together or tear it apart depending on the orientation of the bridging atoms with respect to the cages. We characterize the properties of stable isomers of neutrally charged $\\mathrm{AuGe_{12}}$ and $\\mathrm{Au_2Ge_{12}}$, seeing that radially directed molecular orbitals stabilize $\\mathrm{AuGe_{12}}$ while a geometric asymmetry stabilizes $\\mathrm{Au_2Ge_{12}}$ and $\\mathrm{Au_3Ge_{18}}$. We examine a two-dimensional $_2^\\infty[\\mathrm{Au_2Ge_{6}}]$ structure, finding it more stable than other periodic $[\\mathrm{Au_nGe_{6}}]$ subunits. We observe no stable neutral isomers of $\\mathrm{Au_3Ge_{12}}$, but see that additional charge supports isomers of both $\\mathrm{Au_2Ge_{12}}$ and $\\mathrm{Au_3Ge_{12}}$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-08-12T14:09:16.000Z",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2015-03-05T15:11:26.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "theoretical study",
      "directed molecular orbitals stabilize",
      "short molecular dynamics simulations",
      "additional charge supports isomers",
      "geometric asymmetry stabilizes"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 19,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014arXiv1408.2715M"
    }
  }
}