  Performing electronic structure calculations for large systems, such as
nanoparticles or metal clusters, via orbital based Hartree-Fock or Kohn-Sham
theories is computationaly demanding. To study such systems, therefore, we have
taken recourse to the hydrodynaic approach to time-dependent density functonal
theory. In this paper we develop variation-perturbation method within this
theory in terms of the particle and the current densities of a system. We then
apply this to study the linear and nnlinear resonse properties of alkali metal
clusters within spherical jellium backgrond model.
