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Ehrlich, Gert Senft, Donna Sue Cowell 2011-05-07T13:10:38Z 2011-05-07T13:10:38Z 10000-01-01 1995 The length of the jumps executed by atoms during diffusion is important for understanding atomic transport in crystal growth. Molecular dynamics simulations suggest that atomic jumps longer than a nearest-neighbor spacing should contribute at elevated temperatures. Attempts have been made in the past to deduce the jump length from the prefactor in the Arrhenius plot, but this is quite an uncertain procedure. To establish the possible contribution of long jumps in atomic migration, observations have been made in a field ion microscope of single adatoms on W(211), where diffusion is one-dimensional. Experiments with W, Pd, and Ni adatoms reveal that diffusion obeys a simple Arrhenius relation, with entirely normal prefactors. However, a more definitive way of finding jump lengths is to measure and analyze the distribution function for atomic displacement. Such experiments have been carried out and show that W moves entirely by single jumps, but Ni has occasional double jumps even at the lowest temperature examined. These double jumps make up 6% of the total. As the temperature is increased the number of long jumps for Ni is unchanged, while Pd shows a large increase in the numbers of long jumps. At 133 K, jumps spanning two nearest-neighbor distances make up 15% of the total jumps for palladium, and jumps spanning three nearest-neighbor distances make up 12% of the total. These results are the first indication of long jumps in one-dimensional diffusion. Made available in DSpace on 2011-05-07T13:10:38Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9522172.pdf: 3449079 bytes, checksum: f51e8b773f09acacc2c8b21dad97c3d9 (MD5) Previous issue date: 1995 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:51:16Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:23:30-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9522172 (UMI)AAI9522172 http://hdl.handle.net/2142/21508 eng Copyright 1995 Senft, Donna Sue Cowell Chemistry, Physical Physics, Condensed Matter Engineering, Materials Science Long jumps in surface diffusion on tungsten(211) text Materials Science and Engineering Materials Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.