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Title: | Thermoelastic and dynamical properties of perfluoroethane |
Author(s): | Zeng, Shu-Xiang |
Doctoral Committee Chair(s): | Simmons, R.O. |
Department / Program: | Chemistry, Physical Physics, Molecular Physics, Condensed Matter |
Discipline: | Chemistry, Physical Physics, Molecular Physics, Condensed Matter |
Degree Granting Institution: | University of Illinois at Urbana-Champaign |
Degree: | Ph.D. |
Genre: | Dissertation |
Subject(s): | Chemistry, Physical
Physics, Molecular Physics, Condensed Matter |
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$\sb6$. |
Issue Date: | 1996 |
Type: | Text |
Language: | English |
URI: | http://hdl.handle.net/2142/23770 |
ISBN: | 9780591199819 |
Rights Information: | Copyright 1996 Zeng, Shu-Xiang |
Date Available in IDEALS: | 2011-05-07 |
Identifier in Online Catalog: | AAI9712499 |
OCLC Identifier: | (UMI)AAI9712499 |
This item appears in the following Collection(s)
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Dissertations and Theses - Physics
Dissertations in Physics -
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois