{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23770"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23770","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Thermoelastic and dynamical properties of perfluoroethane","abstract":"Neutron scattering and diffraction were used to measure momentum distributions of carbon and fluorine atoms and diffraction patterns of solid C$\\sb2$F$\\sb6$ from 20 K up to its melting point of 173.3 K, and the momentum distributions of carbon and fluorine in liquid C$\\sb2$F$\\sb6$ at 180 K. At high temperatures, heavy diffuse scattering indicates much molecular orientational disorder. On cooling, a structural phase transformation from bcc crystal to triclinic crystal was verified at 103 K. The mean square momentum of fluorine atoms increases with temperature in the lower temperature solid phase but shows little temperature dependence in the higher temperature solid phase, with no significant change below and above the melting temperature. X-ray diffraction was used to measure temperature dependence of lattice parameter for the bcc solid and to characterize crystalline perfection. A measurement of longitudinal elastic wave velocity in the bcc phase was made, and a set of thermoelastic properties, including longitudinal and transverse velocities of sound, adiabatic and isothermal compressibility, elastic Debye temperature, Gruneisen parameter, heat capacity at constant volume, intramolecular and librational components of heat capacity were calculated for a range of temperatures for the bcc phase. Comparisons of the data to a model with hindered rotation of the molecules were made. Many C$\\sb2$F$\\sb6$ properties were found to be similar to those of SF$\\sb6$.","abstract_html":"Neutron scattering and diffraction were used to measure momentum distributions of carbon and fluorine atoms and diffraction patterns of solid C$\\sb2$F$\\sb6$ from 20 K up to its melting point of 173.3 K, and the momentum distributions of carbon and fluorine in liquid C$\\sb2$F$\\sb6$ at 180 K. At high temperatures, heavy diffuse scattering indicates much molecular orientational disorder. On cooling, a structural phase transformation from bcc crystal to triclinic crystal was verified at 103 K. The mean square momentum of fluorine atoms increases with temperature in the lower temperature solid phase but shows little temperature dependence in the higher temperature solid phase, with no significant change below and above the melting temperature. X-ray diffraction was used to measure temperature dependence of lattice parameter for the bcc solid and to characterize crystalline perfection. A measurement of longitudinal elastic wave velocity in the bcc phase was made, and a set of thermoelastic properties, including longitudinal and transverse velocities of sound, adiabatic and isothermal compressibility, elastic Debye temperature, Gruneisen parameter, heat capacity at constant volume, intramolecular and librational components of heat capacity were calculated for a range of temperatures for the bcc phase. Comparisons of the data to a model with hindered rotation of the molecules were made. Many C$\\sb2$F$\\sb6$ properties were found to be similar to those of SF$\\sb6$.","abstract_has_math":true,"creators":["Zeng, Shu-Xiang"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry, Physical","degree_department":null,"school":null,"contributors":["Simmons, R.O."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"10000-01-01","date_published":"10000-01-01","updated_at":"2026-07-22T22:25:22Z","subjects":["Chemistry, Physical","Physics, Molecular","Physics, Condensed Matter"],"languages":["eng"],"rights":["Copyright 1996 Zeng, Shu-Xiang"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591199819","AAI9712499","(UMI)AAI9712499"],"render_values":[{"text":"9780591199819","href":null,"code":true},{"text":"AAI9712499","href":null,"code":true},{"text":"(UMI)AAI9712499","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23770","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":["Zeng, Shu-Xiang"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["10000-01-01","1996","2011-05-07T14:26:26Z"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry, Physical","Physics, Molecular","Physics, Condensed Matter"]},{"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, Molecular","Physics, Condensed Matter"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1996 Zeng, Shu-Xiang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591199819","AAI9712499","(UMI)AAI9712499","http://hdl.handle.net/2142/23770"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Neutron scattering and diffraction were used to measure momentum distributions of carbon and fluorine atoms and diffraction patterns of solid C$\\sb2$F$\\sb6$ from 20 K up to its melting point of 173.3 K, and the momentum distributions of carbon and fluorine in liquid C$\\sb2$F$\\sb6$ at 180 K. At high temperatures, heavy diffuse scattering indicates much molecular orientational disorder. On cooling, a structural phase transformation from bcc crystal to triclinic crystal was verified at 103 K. The mean square momentum of fluorine atoms increases with temperature in the lower temperature solid phase but shows little temperature dependence in the higher temperature solid phase, with no significant change below and above the melting temperature. X-ray diffraction was used to measure temperature dependence of lattice parameter for the bcc solid and to characterize crystalline perfection. A measurement of longitudinal elastic wave velocity in the bcc phase was made, and a set of thermoelastic properties, including longitudinal and transverse velocities of sound, adiabatic and isothermal compressibility, elastic Debye temperature, Gruneisen parameter, heat capacity at constant volume, intramolecular and librational components of heat capacity were calculated for a range of temperatures for the bcc phase. Comparisons of the data to a model with hindered rotation of the molecules were made. Many C$\\sb2$F$\\sb6$ properties were found to be similar to those of SF$\\sb6$.","Made available in DSpace on 2011-05-07T14:26:26Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712499.pdf: 4510915 bytes, checksum: 3f362999302f6092c3ccd040d3c4a13c (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:06:43Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:32:03-05:00 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":["Thermoelastic and dynamical properties of perfluoroethane"]}]}],"canonical_facts":{"dc:contributor":["Simmons, R.O."],"dc:creator":["Zeng, Shu-Xiang"],"dc:date":["10000-01-01","1996","2011-05-07T14:26:26Z"],"dc:description":["Neutron scattering and diffraction were used to measure momentum distributions of carbon and fluorine atoms and diffraction patterns of solid C$\\sb2$F$\\sb6$ from 20 K up to its melting point of 173.3 K, and the momentum distributions of carbon and fluorine in liquid C$\\sb2$F$\\sb6$ at 180 K. At high temperatures, heavy diffuse scattering indicates much molecular orientational disorder. On cooling, a structural phase transformation from bcc crystal to triclinic crystal was verified at 103 K. The mean square momentum of fluorine atoms increases with temperature in the lower temperature solid phase but shows little temperature dependence in the higher temperature solid phase, with no significant change below and above the melting temperature. X-ray diffraction was used to measure temperature dependence of lattice parameter for the bcc solid and to characterize crystalline perfection. A measurement of longitudinal elastic wave velocity in the bcc phase was made, and a set of thermoelastic properties, including longitudinal and transverse velocities of sound, adiabatic and isothermal compressibility, elastic Debye temperature, Gruneisen parameter, heat capacity at constant volume, intramolecular and librational components of heat capacity were calculated for a range of temperatures for the bcc phase. Comparisons of the data to a model with hindered rotation of the molecules were made. Many C$\\sb2$F$\\sb6$ properties were found to be similar to those of SF$\\sb6$.","Made available in DSpace on 2011-05-07T14:26:26Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712499.pdf: 4510915 bytes, checksum: 3f362999302f6092c3ccd040d3c4a13c (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:06:43Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:32:03-05:00 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"],"dc:identifier":["9780591199819","AAI9712499","(UMI)AAI9712499","http://hdl.handle.net/2142/23770"],"dc:language":["eng"],"dc:rights":["Copyright 1996 Zeng, Shu-Xiang"],"dc:subject":["Chemistry, Physical","Physics, Molecular","Physics, Condensed Matter"],"dc:title":["Thermoelastic and dynamical properties of perfluoroethane"],"dc:type":["text"],"thesis:degree_discipline":["Chemistry, Physical","Physics, Molecular","Physics, Condensed Matter"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:22Z"}