Date of Award


Degree Type


Degree Name

Doctor of Philosophy


High resolution (0.05 eV) Si 2p pre-edge photoabsorption spectra of SiH{dollar}\sb4{dollar}, SiD{dollar}\sb4{dollar}, Si{dollar}\sb2{dollar}H{dollar}\sb6{dollar} and Si{dollar}\sb3{dollar}H{dollar}\sb8{dollar} show a large number of peaks due to Si 2p {dollar}\to{dollar} Rydberg transitions, along with rich vibrational structure. The SiD{dollar}\sb4{dollar} spectrum has been very useful in distinguishing between Rydberg states and vibrational excitations. The spectra of Si{dollar}\sb2{dollar}H{dollar}\sb6{dollar} and Si{dollar}\sb3{dollar}H{dollar}\sb8{dollar} are very similar to each other, exhibiting excitation of asymmetric Si-H vibrations.;The Si L- and K-edge XANES spectra of Si(OCH{dollar}\sb3)\sb{lcub}\rm X{rcub}{dollar}(CH{dollar}\sb3)\sb{lcub}\rm 4-X{rcub}{dollar} (X = 0-4) are reported and the two end members of the series, Si(OCH{dollar}\sb3)\sb4{dollar} and Si(CH{dollar}\sb3)\sb4{dollar}, are compared to the spectra of SiO{dollar}\sb2{dollar} and SiC. The L-edge spectra of gaseous Si(OCH{dollar}\sb3)\sb4{dollar} and solid SiO{dollar}\sb2{dollar} are qualitatively identical, while the L-edge spectra of Si(CH{dollar}\sb3)\sb4{dollar} and SiC show strong similarities. MX-X{dollar}\alpha{dollar} calculations for the two species Si(OCH{dollar}\sb3)\sb4{dollar} were used to assign the various spectra for both compounds. Assignments for SiO{dollar}\sb2{dollar} are based upon a molecular orbital interpretation of the electronic structure of this compound.;High resolution ({dollar}\sim{dollar}0.1 eV) Si 2p gas-phase photoelectron spectra of 24 compounds are reported: SiH{dollar}\sb{lcub}\rm X{rcub}{dollar}D{dollar}\sb{lcub}\rm 4-X{rcub}{dollar}; Si(CH{dollar}\sb3)\sb{lcub}\rm X{rcub}{dollar}(OCH{dollar}\sb3)\sb{lcub}\rm 4-X{rcub}{dollar}; Si(CH{dollar}\sb3)\sb{lcub}\rm X{rcub}{dollar} (N(CH{dollar}\sb3)\sb2\rbrack\sb{lcub}\rm 4-X{rcub}{dollar}; SiH{dollar}\sb{lcub}\rm X{rcub}{dollar} (Si(CH{dollar}\sb3)\sb3\rbrack\sb{lcub}\rm 4-X{rcub}{dollar}; (X = 0-4), and SiH{dollar}\sb3{dollar}-CH{dollar}\sb3{dollar}, SiH{dollar}\sb3{dollar}-SiH{dollar}\sb3{dollar}, SiH{dollar}\sb3{dollar}-SiH{dollar}\sb2{dollar}-SiH{dollar}\sb3{dollar}, Si(CH{dollar}\sb3)\sb3{dollar}-Si(CH{dollar}\sb3)\sb3{dollar}, Ge (Si(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} and (Si(CH{dollar}\sb3)\sb2\rbrack\sb6{dollar}. Vibrational excitations have been resolved in the spectra of SiH{dollar}\sb{lcub}\rm X{rcub}{dollar}D{dollar}\sb{lcub}\rm 4-X{rcub}{dollar}, SiH{dollar}\sb3{dollar}-CH{dollar}\sb3{dollar}, SiH{dollar}\sb3{dollar}-SiH{dollar}\sb3{dollar} and SiH{dollar}\sb3{dollar}-SiH{dollar}\sb2{dollar}-SiH{dollar}\sb3{dollar}. For the compounds {dollar}\rm SiH\sb{lcub}X{rcub}D\sb{lcub}4-X{rcub}{dollar} and SiH{dollar}\sb3{dollar}-CH{dollar}\sb3{dollar} the vibrational structure is dominated by the Si-H, Si-D or Si-C symmetric vibrational mode. Conversely, the spectra of SiH{dollar}\sb3{dollar}-SiH{dollar}\sb3{dollar} and SiH{dollar}\sb3{dollar}-SiH{dollar}\sb2{dollar}-SiH{dollar}\sb3{dollar} are dominated by the asymmetric Si-H bending vibrations--the first example of this in core-level photoelectron spectroscopy. In the remaining compounds the vibrational effects are not resolved; however, the peak widths increase in the order Si(CH{dollar}\sb3)\sb4<{dollar} Si (Si(CH{dollar}\sb3)\sb3\rbrack\sb4<{dollar} Si (N(CH{dollar}\sb3)\sb2\rbrack\sb4<{dollar} Si(OCH{dollar}\sb3)\sb4<{dollar} SiF{dollar}\sb4{dollar} indicating that the vibrational manifold increases analogously.;The valence photoelectron spectra of Si(CH{dollar}\sb3)\sb4{dollar}, Si(CH{dollar}\sb3)\sb3{dollar}-Si(CH{dollar}\sb3)\sb3{dollar}, Si (Si(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar}, Ge (Si(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} and (Si(CH{dollar}\sb3)\sb2\rbrack\sb6{dollar} are reported at four different photon energies, 21.2, 100, 120 and 135 eV.



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