  We develop a quantum-mechanical theory for Landau damping of surface plasmons
in metal nanostructures larger that the characteristic length for nonlocal
effects. We show that the electron surface scattering, which facilitates
plasmon decay in small nanostructures, can be incorporated into the metal
dielectric function on par with phonon and impurity scattering. The derived
surface scattering rate is determined by the plasmon local field polarization
relative to the metal-dielectric interface and is highly sensitive to the
system geometry. We illustrate our model by providing analytical results for
surface scattering rate in some common shape nanostructures.
