Potential modulation of equilibrium and excitation phenomena at the electrolyte-solid interface
Abstract
This progress report covers the work accomplished from the beginning of Sep. 1990, through Sep. 1991. This includes the final portion of the last funding period as well as the first 7 months of the new period. During this time we have pursued our goal of studying the role of the interfacial potential difference in determining the ground and excited electronic states of the electrolyte solid system. Ours is a program designed to provide fundamental information about this complicated environment. We seek to improve the techniques with which electrochemical interfaces can be studied and thereby observe details which have never before been measured. We are primarily concerned with optical techniques, but have also integrated conventional and non-conventional supplementary methods. We have developed the technique of optical second harmonic generation into a spectroscopy by performing the experiment with a wide range of nearly continuous incident photon energies. Through this advantage we have performed detailed tests of the interfacial potential as derived through local density functional methods in the jellium limit. Our data show that the theory is reasonably satisfactory when the surface is electron deficient. However, when the surface is negatively charged (electron excess) significant discrepancies are evident. At least part of this deviation has been explained by transitions involving potential modulated surface states. This project has helped clarify some important questions concerning the nonlinear optical properties of metals, as well as lay the ground work for future applications aimed at monitoring adsorption phenomena with optical second harmonic reflectance spectroscopy.
- Publication:
-
Unknown
- Pub Date:
- October 1991
- Bibcode:
- 1991pmee.rept.....F
- Keywords:
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- Electrolytes;
- Ground State;
- Harmonic Generators;
- Interfaces;
- Modulation;
- Electrochemistry;
- Electrodes;
- Excitation;
- Microbalances;
- Silver;
- Spectroscopy;
- Atomic and Molecular Physics