[Ifeffit] idealized 95-atom Pt cluster

Anatoly Frenkel frenkel at bnl.gov
Mon May 16 21:23:46 CDT 2005


[Ifeffit] idealized 95-atom Pt clusterCharles,

The 95 atoms Pt cluster you describe sounds strange. It does not fit any
sequence of magic numbers typical for regular polyhedral clusters (13, 55,
147... for cuboctahedral fcc and icosahedral clusters,  or 13, 38, 79,
140... for truncated octahedral or : 10, 37, 92, 185...for supported
cuboctahedral clusters).

If you are modeling an fcc cluster (Pt does pack into fcc structure, even
for sizes smaller than your clusters, contrary, e.g., to Au which is
possible to observer in icosahedral structure for 13-atom clusters) then
your "spherical" cluster of 95 atoms is not a closed shell cluster and thus
it is not a stable isomer. What are you trying to accomplish?

Anatoly

Anatoly Frenkel


  -----Original Message-----
  From: ifeffit-bounces at millenia.cars.aps.anl.gov
[mailto:ifeffit-bounces at millenia.cars.aps.anl.gov]On Behalf Of Charles
Chusuei
  Sent: Monday, May 16, 2005 4:48 PM
  To: ifeffit at millenia.cars.aps.anl.gov
  Subject: [Ifeffit] idealized 95-atom Pt cluster


  Hi,,,

  I'm a new user to Artemis and Atoms. I would like to generate a simulated
  EXAFS spectrum of an idealized bare 95-atom cluster of Pt (with no ligands
  attached to it).  Looking at Cambridge data files, the largest cluster
  documented is 18, so I would have to make one up.  I would like to arrange
  the 95 atoms into an idealized sphere with the standard geometry for bulk
  Pt-Pt bonding that can be predicted from the crystal structure (e.g.
  metallic radius = 139nm, metallic separation = 277.5nm separation, etc.)

  I understand this can be done using Artemis and Atoms.  I'm relatively new
  to using the software (prodominantly know how to use Athena for plotting
  the experimental EXAFS data , not much more).

  Could anyone provide suggestions on how to get started on this task? E.g.
  Generating the crystal data and displaying the EXAFS of the resulting bare
  cluster?



  Charles

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