POLARON EFFECTS ON ELECTRONIC-PROPERTIES OF METAL MEDIUM INTERFACES .2. ELECTRIFIED INTERFACES - IN-SITU 2ND-HARMONIC GENERATION/

The linear and non-linear response of a charged metal dielectric inter face to an electromagnetic held is considered within the jellium diele ctric model as developed in the preceding paper. The response to the e lectromagnetic held is considered for two realistic held frequencies: (i) the frequency is lower than the typical frequencies of the medium and the metal, (ii) the frequency lies in the optical transparency ban d of the dielectric. The linear response is calculated in terms of the location of the image plane and the non-linear response in terms of t he Rudnick-Stern parameter which determines the isotropic part of the second harmonic generation signal. Significantly it is found that incr eased screening by the slow, dipolar modes of the dielectric cause the magnitude of the Rudnick-Stern parameter to increase, while an increa se in the screening by the fast, electronic modes causes the magnitude of the Rudnick-Stern parameter to decrease.