Ab initio calculation of the nonlinear susceptibility χ (2) of a crystal surface

Abstract

The polarizability and first hyperpolarizability of a crystal surface are calculated from a sum over states method using crystalline orbitals of the CRYSTAL program. The linear and nonlinear optical properties of the (001) LiF surfaces are evaluated layer by layer, showing that the response of inner layers to an electric field tends effectively to the bulk response value while the χ⁽²⁾ susceptibility components responsible of second harmonic generation (SHG) are no longer equal to zero at the surface of the crystal.