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dc.contributor.authorDetrie, Theresa A.en_US
dc.date.accessioned2014-03-14T20:47:53Z
dc.date.available2014-03-14T20:47:53Z
dc.date.issued2008-11-03en_US
dc.identifier.otheretd-11142008-092001en_US
dc.identifier.urihttp://hdl.handle.net/10919/35702
dc.description.abstractThe mineral prehnite, Ca2(Al,Fe,Mn)(AlSi3O10)(OH)2, is a layered structure consisting of double-sheets of (Al,Si)O4 and SiO4 tetrahedra alternating with single sheets of AlO4(OH)2 octahedra. To understand the ordering in the structure and differences between various samples of prehnite, single-crystal X-ray diffraction data at ambient conditions were collected on four single crystals of prehnite from different localities. The positions of the H atoms have been determined for the first time, from a combination of X-ray and neutron diffraction data. The equation of state and high-pressure behavior of prehnite have been investigated using single-crystal X-ray diffraction up to 9.75(3) GPa. A second-order Birchâ Murnaghan equation of state fit to the isothermal P-V data to 8.7 GPa yields a bulk modulus, K = 109.29(18) GPa. Structural data collected at high pressures indicate that the structure compresses uniformly. Above 8.7 GPa there is additional softening of the volume and the b-axis related to polyhedral tilting. However, the average structure is maintained across the transition. Ambient and high-pressure Raman and synchrotron infrared spectra were collected from 1 bar to 20 GPa. Raman spectra measured at ambient conditions of four prehnite crystals with different compositions confirmed that there are no structural changes with different compositions. High-pressure results showed the majority of modes shift to higher frequencies (in a smooth, linear fashion) with increasing pressure. The greatest change in the spectra is the softening of the modes in the OH-stretching region above 9 GPa, thought to be related to the polyhedral tilting around the H environment.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartETD_t.detrie_MSv6.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectprehniteen_US
dc.subjecthigh-pressureen_US
dc.subjectX-ray diffractionen_US
dc.subjectneutron diffractionen_US
dc.subjectspectroscopyen_US
dc.subjecthydrogenen_US
dc.titlePrehnite at the Atomic Scale: Al/Si Ordering, Hydrogen Environment, and High-Pressure Behavioren_US
dc.typeThesisen_US
dc.contributor.departmentGeosciencesen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineGeosciencesen_US
dc.contributor.committeechairRoss, Nancy L.en_US
dc.contributor.committeememberAngel, Ross J.en_US
dc.contributor.committeememberBallaran, Tiziana Boffaen_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11142008-092001/en_US
dc.date.sdate2008-11-14en_US
dc.date.rdate2008-12-10
dc.date.adate2008-12-10en_US


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