{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/21508"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/21508","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Long jumps in surface diffusion on tungsten(211)","abstract":"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.","abstract_html":"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.","abstract_has_math":false,"creators":["Senft, Donna Sue Cowell"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Engineering","degree_department":null,"school":null,"contributors":["Ehrlich, Gert"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:10:38Z","date_published":"2011-05-07T13:10:38Z","updated_at":"2026-07-22T22:25:18Z","subjects":["Chemistry, Physical","Physics, Condensed Matter","Engineering, Materials Science"],"languages":["eng"],"rights":["Copyright 1995 Senft, Donna Sue Cowell"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9522172","(UMI)AAI9522172"],"render_values":[{"text":"AAI9522172","href":null,"code":true},{"text":"(UMI)AAI9522172","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/21508","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Ehrlich, Gert"]},{"key":"dc:creator","label":"Author","values":["Senft, Donna Sue Cowell"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:10:38Z","10000-01-01","1995"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Physical","Physics, Condensed Matter","Engineering, Materials Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1995 Senft, Donna Sue Cowell"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9522172","(UMI)AAI9522172","http://hdl.handle.net/2142/21508"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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"]},{"key":"dc:title","label":"Title","values":["Long jumps in surface diffusion on tungsten(211)"]}]}],"canonical_facts":{"dc:contributor":["Ehrlich, Gert"],"dc:creator":["Senft, Donna Sue Cowell"],"dc:date":["2011-05-07T13:10:38Z","10000-01-01","1995"],"dc:description":["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). 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