Interference of Linear and Nonlinear Optical Effects in Second-Harmonic Generation from Metal/Liquid Interfaces

Author: Walters M. J.   Roy D.  

Publisher: Society for Applied Spectroscopy

ISSN: 0003-7028

Source: Applied Spectroscopy, Vol.52, Iss.12, 1998-12, pp. : 1554-1568

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Abstract

When a metal/liquid interface is probed with second-harmonic generation, the experimental data can be severely complicated by mixed signatures of linear and nonlinear optical properties of the interface. This problem is demonstrated and clarified in this report with computer simulations for selected electrochemical systems. A phenomenological framework for these simulations is developed. The first- and second-order surface susceptibilities of the metal are treated on equal footing, and their variations due to adsorbate effects are analyzed. Analytical and simulated results are presented for two specific groups of adsorbates. Representative experimental systems of these two groups (electrodeposited Cu and Te on polycrystalline Au) are analyzed in further detail. The calculations are in full agreement with the previously published experimental data for these systems. The present formalism can be extended to other systems and, in a systematic manner, can facilitate the analysis of second-harmonic data for electrochemical systems.