  The exact numerical diagonalization of the Hamiltonian of a 2D circular
quantum dot is performed for 2, 3, and 4 electrons.The results are compared
with those of the perturbation theory.Our numerical results agree reasonably
well for small values of the dimensionles coupling constant \lambda=a\over a_B
where a is the dot radius and a_B is the effective Bohr radius.Exact
diagonalization results are compared with the classical predictions, and they
are found to be almost coincident for large \lambda values. PACS Numbers:
73.20.Dx, 73.61.-r
