Nonlinear polarizabilities of atoms from their ground-state densities

Using density based perturbation theory [M.K. Harbola, A. Banerjee, Phys. Lett. A 222, 315 (1996)], we calculate the static hyperpolarizabilty gamma for spherical atoms and ions from their ground-state densities. Since densities are being employed, calculations are performed using approximate functionals for the kinetic and the exchange-correlation energies. Use of densities-instead of the wavefunctions or Kohn-Sham orbitals-reduces the computational effort substantially. The results obtained are within 5%-15% of those calculated from the corresponding orbital-based calculations.