Interference second harmonic anisotropy at single crystalline silver-electrodes

Using a new approach, the interference SHG anisotropy, it is possible to un ambiguously evaluate the nonlinear susceptibility coefficients, which descr ibe the isotropic and anisotropic response of a metal electrode. We report on a first application of this method to single crystalline silver electrod es in a 50 mM aqueous solution of NaClO4. The isotropic coefficient a shows the strongest dependence on the electrode potential. Theory predicts that the real part a(r) = Re(a) should have a minimum near the potential of zero charge. A normalized plot of a(r) vs. the surface charge density sigma sho ws a good agreement between experiment and theory in the range -20 mu C cm( -2) < sigma < 20 mu C cm(-2) (C) 1998 Elsevier Science Ltd. All rights rese rved.