Second-harmonic generation at metal surfaces using an extended Thomas Fermi von Weizsacker theory

An extended ThomasFermivon Weizsacker theory is used to investigate the properties of simple metal surfaces. Fundamental surface quantities such as the work function and surface energy are found to compare quite favorably with the corresponding results obtained through the use of density-functional theory. Application of the method to the calculation of second-harmonic response in the low-frequency limit yields results in essential agreement with the recent self-consistent density-functional calculations of Weber and Liebsch.