Static field effect on the band intensity of adsorbed sulfate ions

The effect of the static electric field at the electrochemical interface on the band intensity for the symmetric S-O stretch of adsorbed sulfate ions on polycrystalline platinum electrodes is analyzed. A quadratic dependence of the band intensity on the static electric field is found. A model based on the field induced change of the dynamic dipole moment furnishes data on the dynamic dipole moment and the dynamic polarizability of adsorbed SO42-. The measured (partial derivative mu(0)/partial derivative Q(k)) is 89.5 esu g(-1/2), and (partial derivative alpha/partial derivative Q(k)) is a function of coverage, ranging between 7.9 x 10(-4) and 11.6 x 10(-4) cm(2) g(1-/2).