The ultraviolet photoelectron spectroscopy of Group IV 2-15 atom cluster anions

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dc.contributor.advisorSmalley, Richard E.en_US
dc.creatorCraycraft, Mary Joen_US
dc.date.accessioned2009-06-04T00:26:28Zen_US
dc.date.available2009-06-04T00:26:28Zen_US
dc.date.issued1989en_US
dc.description.abstractThe ability to map valence electronic structure is the result of a recent advance in photoelectron spectroscopy; its union with cluster molecular beam technology. The task of interpreting the spectra is hampered by a serious lack of understanding of cluster electronic structure in general. Recently progress has been made in finding models for single s valence electron systems. Alkali and noble metal clusters can be treated as free electron systems and simple interatomic potentials can be used with rare gas clusters. Neither a smeared jellium background nor a simple interatomic potential is adequate to describe covalent bonding, however. The isoelectronic Group IV members have a valence configuration of ns$\sp2$np$\sp2$. All readily form clusters, and the elements differ in both their atomic and bulk properties; thus the series provides an ideal system for studying electronic structure. The mass selected cluster ion beam is crossed with a beam (6.42 or 7.9eV) and the resulting photodetached electrons collected with the aid of judiciously arranged magnetic fields. The spectra are found to be unique for each size cluster. Some spectra show a significant gap between the two lowest binding energy features, indicating that the neutral cluster is a closed shell species. The clusters with such gaps are minima in a plot of EA as a function of cluster size. The UPS also vary with the cluster composition. Carbon is unique; an even -odd alternation in electron affinities switches from odd minima for clusters containing less than ten atoms to odd maxima for larger clusters. This corresponds with an alternation in singlet and triplet ground states and a switch from chain to ring structures previously predicted by theory (K. S. Pitzer, E. Clementi, J. Amer. Chem. Soc. 81 4477 (1958) and R. Hoffmann, Tetrahedron 22 521 (1965)). The spectra of the remaining group IV members are remarkably similar to each other for clusters of up to ten atoms, as is the trend in the electron affinities as a function of cluster size. This similarity in electronic structure may imply similarity in geometries. At ten, Si and Ge behavior diverges from that of Sn and Pb.en_US
dc.format.extent180 p.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.callnoThesis Chem. 1989 Craycraften_US
dc.identifier.citationCraycraft, Mary Jo. "The ultraviolet photoelectron spectroscopy of Group IV 2-15 atom cluster anions." (1989) Diss., Rice University. <a href="https://hdl.handle.net/1911/16222">https://hdl.handle.net/1911/16222</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/16222en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectPhysical chemistryen_US
dc.subjectMolecular physicsen_US
dc.titleThe ultraviolet photoelectron spectroscopy of Group IV 2-15 atom cluster anionsen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentChemistryen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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