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Mochel, J.M. Vanfleet, Richard R. 2012-04-26T20:07:06Z 2012-04-26T20:07:06Z 10000-01-01 1997 Small metal particles in the range of a few nanometers in diameter are seen to progressively disorder when the 100 keV electron beam of a Scanning Transmission Electron Microscope (STEM) is held stationary on the particle. The diffraction pattern of the individual particle is seen to progress from an initial array of indexable diffraction spots to a mixture of diffraction spots and amorphous-like rings and finally to rings with no persistent diffraction spots. Only particles below a critical size are seen to fully disorder. We have observed this disordering in Platinum, Palladium, Rhodium, and Iridium and have developed a model for the disordering process. In this model, electrons scattering from surface atoms transfer enough energy to break the surface atoms from their binding site. A competing process of disordered atoms rebinding to crystalline sites is also included. Because small particles have large fractions of their atoms on the surface, the beam driven disorder, under certain conditions, is able to propagate into the core of the particle. For Platinum, surface disordering requires energy transfers from the electrons to the Platinum atoms of0.54 eV. Submitted by Megan O'Donnell (mnodonn2@illinois.edu) on 2012-04-26T20:07:06Z No. of bitstreams: 1 1997_vanfleet.pdf: 4016013 bytes, checksum: 9c48f6d466713ed4c0d8e680355ff02c (MD5) Made available in DSpace on 2012-04-26T20:07:06Z (GMT). No. of bitstreams: 1 1997_vanfleet.pdf: 4016013 bytes, checksum: 9c48f6d466713ed4c0d8e680355ff02c (MD5) Previous issue date: 1997 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Megan O'Donnell (mnodonn2@illinois.edu) on 2012-04-26T20:07:06Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:34:51-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: dissertation/thesis dissertation/thesis U of I Only 4048920 http://hdl.handle.net/2142/30770 en © 1997 Richard R. Vanfleet Scanning Transmission Electron Microscope (STEM) platinum palladium rhodium iridium electron scattering in metals diffraction patten thermodynamics small metal particles Disordering of small metal particles in a scanning transmission electron microscope Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.