Interrogating the Electrochemical Interface Using Sum Frequency Generation Spectroscopy

Abstract

SFG in tandem with electrochemical capacitance and CV measurements are used to study the effects of applied potential on the adsorption and orientation of PABA at a Ag(111) surface. The data indicates that PABA changes orientation in response to the charge on the electrode surface, orienting one way positive of the potential of zero charge (pzc) and oppositely negative of the pzc. At positive potentials a phase change is observed associated with the formation of a condensed layer. These results show that the orientation of small molecule zwitterions can be controlled by applied potential.