THE 2ND-HARMONIC RESPONSE OF SINGLE-CRYSTAL SILVER ELECTRODES OBTAINED WITH AN INTERFERENCE METHOD

The second-harmonic response of several single-crystal silver electrod es is investigated at a long wavelength. In contrast to earlier experi ments, the phase of the signal is obtained directly by an interference method. By comparing measurements at two different angles of incidenc e, the Rudnick-Stern coefficient characterizing the response perpendic ular to the surface can be estimated; for Ag(100) and Ag(111) it agree s fairly well with calculations based on the jellium model. For the Ag (110) surface, the twofold amplitude depends on the electrode potentia l; in addition, a contribution with a three-fold symmetry is observed. These unexpected features are probably caused by a facetting of the A g(110) surface. (C) 1998 Elsevier Science B.V. All rights reserved.