Author

Lei Li

Date of Award

5-2012

Level of Access

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

Advisor

David J. Neivandt

Second Committee Member

Michael D. Mason

Third Committee Member

Robert J. Lad

Abstract

Sum frequency spectroscopy (SFS) is a surface specific non-linear pulsed laser technique capable of providing detailed molecular-level orientation and conformational information of interfacial species. Application of this technique to thin film structures results in complex spectra which require theoretical deconvolution. In the present work, a new co-propagating model for SF emission from model cellulose surfaces has been developed, thereby enabling the study of cellulose surface characteristics and various aspects of wood utilization. Immobilized model cellulose films have been prepared on gold coated silicon wafers for characterization by SFS.

Before quantitatively analyzing SF spectra derived from cellulose, the thickness dependent interference effect between multiple SF sources in the cellulose/gold system was investigated theoretically. Comparisons between experimental and simulated SF spectra enable an accurate understanding of thickness/phase and thickness/intensity

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