xvi, 145 p. : ill. (some col.) / The structures of several compounds in the [(PbSe)0.99]m[WSe2]n,
[(PbSe)1.00]1[MoSe2]1, and [(SnSe)1.03]1[MoSe2]1 systems were determined using x-ray
data. The structural determination using Rietveld methods was complicated by the strong
preferred orientation of the samples, which resulted in x-ray diffraction scans with either
00l or hk0 reflections depending on the orientation of the sample in the diffractometer.
Rietveld refinements of the [(PbSe)0.99]1[WSe2]1, [(PbSe)1.00]1[MoSe2]1, and
[(SnSe)1.03]1[MoSe2]1 samples were compared to single crystal sample refinement results
for [(MX)1+d]1[TX2]1, where M is a metal, T is a transition, X is a chalcogen, and d is the
misfit parameter. The structural refinement yielded rock salt layer puckering values of 25
pm, 23 pm, and 36 pm for [(PbSe)0.99]1[WSe2]1, [(PbSe)1.00]1[MoSe2]1, and
[(SnSe)1.03]1[MoSe2]1, respectively, which are all within the established literature range
of 20 pm to 60 pm. The refinement of the hk0 reflections confirmed that the in plane
structures were consistent with the dichalcogenide (P63mmc) and rock salt (Fm3m)
structure types. Structures for the [(PbSe)0.99]m[WSe2]m isomer series where m = 1 to 5 were
determined, and a systematic trend in structure as a function of the thickness of the
constituent layers was discovered. The structure of the rock salt constituent was found to
distort into pairs, forming alternating long and short distances along the c axis. This
distortion decreases as the number of rock salt planes increases from 4 to 6 to 8 and is
either absent or nearly so in compounds with a larger number of rock salt planes. The
puckering distortion at the interface between the rock salt and the dichalcogenide is also
observed in the inner rock salt layers but decreases in magnitude moving away from the
rock salt – dichalcogenide interface.
Structures of [(PbSe)0.99]m[WSe2]n where m = 1 or 2 and n = 1 or 2 were also
determined. The degree of structural distortion is a function of the ratio of rock salt to
dichalcogenide layers.
This dissertation includes unpublished co-authored material. / Committee in charge: Dr. Thomas R. Dyke, Ph.D., Chairperson;
Dr. David C. Johnson, Ph.D., Advisor;
Dr. Catherine J. Page, Ph.D., Member;
Dr. Andrew H. Marcus, Ph.D., Member;
Dr. John L. Hardwick, Ph.D., Member;
Dr. Richard Taylor, Ph.D., Outside Member
| Identifer | oai:union.ndltd.org:uoregon.edu/oai:scholarsbank.uoregon.edu:1794/11580 |
| Date | 06 1900 |
| Creators | Smeller, Mary Magdalene |
| Publisher | University of Oregon |
| Source Sets | University of Oregon |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Relation | University of Oregon theses, Dept. of Chemistry, Ph. D., 2011; |
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