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dc.contributor.advisorAllen, R. E.
dc.creatorLawrence, William Reed
dc.description.abstractThree problems were investigated: (1) Reconstruction of fee (100) surface. A few years ago, Burton and Jura showed that an Einstein model predicts a structural phase transition for the (100) surface of Ar at a temperature T (subscript c) below the melting point. One would expect this transition to be experimentally observable in other fcc materials--A1, Ni, etc. In this work, however, we prove that the Burton and Jura model for the reconstructed surface is mechanically unstable and the phase transition is consequently impossible. (2) Vibrational modes of adsorbed atoms. Previous studies of the vibrational spectra of adsorbate-substrate systems have involved "mass defect" models, in which the adsorbate is assumed to differ from the substrate only in mass. Our calculations are for the systems ⁴He on Xe; Ne on Ar, Kr, and Xe; Ar and Kr on Xe; and Kr on Xe; with the proper force constant changes at the surface taken into account. A detailed discussion is given of the vibrational spectra of these systems. We find that the results for "mass defect" models are qualitatively incorrect in two ways: the ordering of the "principal" modes associated with adsorbate vibrations is backwards (with the vertically polarized modes lying below the horizontally polarized modes), and the effect of the adsorbate on the substrate surface modes is too large in the case of weakly bound adsorbates. (3) Heat capacities of adsorption. For the seven systems listed above, we calculated the heat capacities of adsorption. The results for Ne on Ar and Kr are in semiquantitative agreement with the experimental data of Antoniou for Ne on graphite. The results are also in qualitative agreement with the experimental data of Bretz et a l. for He on graphite.en
dc.format.extentviii, 47 leavesen
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subjectHeat of adsorptionen
dc.subjectLattice dynamicsen
dc.subjectPhase transformations (Statistical physics)en
dc.subjectVibrational spectraen
dc.subject.classification1976 Dissertation L424
dc.subject.lcshLattice dynamicsen
dc.subject.lcshPhase transformations (Statistical physics)en
dc.subject.lcshHeat of adsorptionen
dc.subject.lcshVibrational spectraen
dc.titleVibrational properties of adsorbates and reconstructed surfacesen
dc.typeThesisen A&M Universityen of Philosophyen
dc.contributor.committeeMemberNaugle, A. B.
dc.contributor.committeeMemberReading, J. F.
dc.format.digitalOriginreformatted digitalen
dc.publisher.digitalTexas A&M University. Libraries

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