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Many chemical reactions take place at the liquid/solid interface that are responsible for dramatic environmental, industrial and economic problems. For a long time, these reactions have been studied by conventional electrochemical techniques and the influence of most of the macroscopic parameters involved in the reaction (solution pH and composition, redox potential, etc.) are known for many systems. The resulting oxidized surface is often analysed by XPS and AES, but the measurements are performed after air exposure and thus after surface contamination or post-oxidation. Most of the time, no direct information on the surface composition at the liquid/solid interface is available because of the lack of in situ available techniques for chemical analysis.In order to combine the intrinsic advantage of electrochemical techniques (superior for the study of the redox reactions in solution) and the power of surface analysis techniques such as XPS and AES used under ultrahigh vacuum (UHV), we have designed, built and validated an original versatile UHV-electrochemical cell transfer system. This system allows the preparation of a clean electrode surface under UHV and its characterization by low-energy electron diffraction and AES before its transfer to an electrochemical cell under a controlled atmosphere (no oxygen, no contamination). The study of model electrochemical reactions can take place and is followed by transfer of the electrode back to the UHV chamber for surface analysis by AES, without exposure to air. The transfer procedure takes 4 min.Model systems were used to validate the system:(1) Bromide ions were electrochemically adsorbed on gold at various electrode potentials, inducing different surface compositions. Evolution of the Br content on the surface as a function of the electrode potential, estimated after transfer by AES, is in good agreement with the Br surface excess extracted from the electrochemical data, indicating that the transfer process induces no significant alteration of the surface, despite the weak bonding of bromide on gold and the brutal transfer from liquid to UHV. Results were compared with the literature. (2) Aluminium was taken as a standard to study the residual oxidation due to the composition of the atmosphere during the transfer process. The residual contamination (carbon) induced by the transfer process was also analysed. Carbon-free transfer procedures were established.In conclusion, such a transfer system combines the unique advantages of electrochemical methods to study corrosion processes with the power of a UHV technique such as AES.

Reducing the critical thickness of epitaxial Ag film on the Si(111) substrate by introducing a monolayer Al buffer layer Silver deposition onto gold ͑111͒, ͑554͒, and ͑311͒ single crystals was studied by Auger electron spectroscopy and low energy electron diffraction. It is suggested that the growth mechanism depends partly on the atomic roughness of the surface. Growth on the ͑311͒ faces seems to follow a Stranski-Krastanov mode, while growth on Au͑111͒ adopts a Frank-van der Merwe mode. The deposition of one monolayer of silver is required to lift the reconstruction of the Au͑111͒ or ͑554͒ surface.