{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/80672"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/80672","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"X-Ray Debye -Waller Factor Measurements of Helium Crystals","abstract":"The measured results agree well with computational values, made using path integral Monte Carlo methods. The Lindemann ratios were around 0.11 for both isotopes, with the 3He values being larger at similar densities. A 3He-4He mass-scaling factor of 4/3 for the equivalent Debye temperature for the measured Debye-Waller factor was observed. This Debye temperature falls with increasing temperature, contrary to what would be expected for a quasi-harmonic model, most likely due to multi-phonon processes being present in the crystals.","abstract_html":"The measured results agree well with computational values, made using path integral Monte Carlo methods. The Lindemann ratios were around 0.11 for both isotopes, with the 3He values being larger at similar densities. A 3He-4He mass-scaling factor of 4/3 for the equivalent Debye temperature for the measured Debye-Waller factor was observed. This Debye temperature falls with increasing temperature, contrary to what would be expected for a quasi-harmonic model, most likely due to multi-phonon processes being present in the crystals.","abstract_has_math":false,"creators":["Arms, Dohn Alexander"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Ralph O. 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The Lindemann ratios were around 0.11 for both isotopes, with the 3He values being larger at similar densities. A 3He-4He mass-scaling factor of 4/3 for the equivalent Debye temperature for the measured Debye-Waller factor was observed. This Debye temperature falls with increasing temperature, contrary to what would be expected for a quasi-harmonic model, most likely due to multi-phonon processes being present in the crystals.","Made available in DSpace on 2015-09-25T20:03:33Z (GMT). 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