{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25675"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25675","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Lattice parameter and thermal expansion in solid methane","abstract":"The lattice parameter of a methane CH4 single crystal with an oxygen impurity of 0.01% has been measured in the range 2.5 to 86.2 K with a precise, back-reflection x-ray camera. The lattice parameters differ significantly from previous imprecise values in the literature. A first-order transition with a discontinuity in the lattice parameter of 0.1% was unambiguously observed to occur at 20.48 K on warming through the transition and at 20.39 K on cooling through the transition. An intrinsic hysteresis appeared to be present, and its position and width was verified by independent thermal arrest measurements. The average entropy discontinuity was 0.65 cal/mole/deg. A phenomenological study of the data in the range 2.5 to 12 K was made to gain some understanding of the observed negative thermal expansion below 9.75 K. The results of the study were consistent with spin-species conversion at low temperatures. With the use of these precise lattice parameter data and the data of other workers, improved values of the thermodynamic properties of solid methane were obtained.","abstract_html":"The lattice parameter of a methane CH4 single crystal with an oxygen impurity of 0.01% has been measured in the range 2.5 to 86.2 K with a precise, back-reflection x-ray camera. The lattice parameters differ significantly from previous imprecise values in the literature. A first-order transition with a discontinuity in the lattice parameter of 0.1% was unambiguously observed to occur at 20.48 K on warming through the transition and at 20.39 K on cooling through the transition. An intrinsic hysteresis appeared to be present, and its position and width was verified by independent thermal arrest measurements. The average entropy discontinuity was 0.65 cal/mole/deg. A phenomenological study of the data in the range 2.5 to 12 K was made to gain some understanding of the observed negative thermal expansion below 9.75 K. The results of the study were consistent with spin-species conversion at low temperatures. With the use of these precise lattice parameter data and the data of other workers, improved values of the thermodynamic properties of solid methane were obtained.","abstract_has_math":false,"creators":["Aadsen, Duane Rodney"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Simmons, R.O."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-07-06T18:21:27Z","date_published":"2011-07-06T18:21:27Z","updated_at":"2026-07-22T22:25:26Z","subjects":["lattice parameter","thermal expansion","solid methane","methane single crystal"],"languages":["en"],"rights":["1975 Duane Rodney Aadsen"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["2027859"],"render_values":[{"text":"2027859","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25675","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Simmons, R.O."]},{"key":"dc:creator","label":"Author","values":["Aadsen, Duane Rodney"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-07-06T18:21:27Z","10000-01-01","1975"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["lattice parameter","thermal expansion","solid methane","methane single crystal"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1975 Duane Rodney Aadsen"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["2027859","http://hdl.handle.net/2142/25675"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The lattice parameter of a methane CH4 single crystal with an oxygen impurity of 0.01% has been measured in the range 2.5 to 86.2 K with a precise, back-reflection x-ray camera. The lattice parameters differ significantly from previous imprecise values in the literature. A first-order transition with a discontinuity in the lattice parameter of 0.1% was unambiguously observed to occur at 20.48 K on warming through the transition and at 20.39 K on cooling through the transition. An intrinsic hysteresis appeared to be present, and its position and width was verified by independent thermal arrest measurements. The average entropy discontinuity was 0.65 cal/mole/deg. A phenomenological study of the data in the range 2.5 to 12 K was made to gain some understanding of the observed negative thermal expansion below 9.75 K. The results of the study were consistent with spin-species conversion at low temperatures. With the use of these precise lattice parameter data and the data of other workers, improved values of the thermodynamic properties of solid methane were obtained.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-06T18:21:27Z No. of bitstreams: 1 1975_aadsen.pdf: 3735851 bytes, checksum: 7b1b760464ccd422f5de05b1f92db1c8 (MD5)","Made available in DSpace on 2011-07-06T18:21:27Z (GMT). No. of bitstreams: 1 1975_aadsen.pdf: 3735851 bytes, checksum: 7b1b760464ccd422f5de05b1f92db1c8 (MD5) Previous issue date: 1975","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-06T18:21:27Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:32:32-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Lattice parameter and thermal expansion in solid methane"]}]}],"canonical_facts":{"dc:contributor":["Simmons, R.O."],"dc:creator":["Aadsen, Duane Rodney"],"dc:date":["2011-07-06T18:21:27Z","10000-01-01","1975"],"dc:description":["The lattice parameter of a methane CH4 single crystal with an oxygen impurity of 0.01% has been measured in the range 2.5 to 86.2 K with a precise, back-reflection x-ray camera. The lattice parameters differ significantly from previous imprecise values in the literature. A first-order transition with a discontinuity in the lattice parameter of 0.1% was unambiguously observed to occur at 20.48 K on warming through the transition and at 20.39 K on cooling through the transition. An intrinsic hysteresis appeared to be present, and its position and width was verified by independent thermal arrest measurements. The average entropy discontinuity was 0.65 cal/mole/deg. A phenomenological study of the data in the range 2.5 to 12 K was made to gain some understanding of the observed negative thermal expansion below 9.75 K. The results of the study were consistent with spin-species conversion at low temperatures. With the use of these precise lattice parameter data and the data of other workers, improved values of the thermodynamic properties of solid methane were obtained.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-06T18:21:27Z No. of bitstreams: 1 1975_aadsen.pdf: 3735851 bytes, checksum: 7b1b760464ccd422f5de05b1f92db1c8 (MD5)","Made available in DSpace on 2011-07-06T18:21:27Z (GMT). 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