The rotating two electron atom in an external electric field

Three exact rigid-body solutions for a rotating two-electron atom under the influence of an electric field along the rotation axis have been obtained with a classical approach. The stability analysis of the linearized motions around each of the equilibrium motions was made for different values of the electric field. We find an exact solution, which in the zero case, gives a known solution as a rotor, another exact solution which in the zero field case gives the Wannier unbound solution, and a numerical solution which in the zero field case gives the asymmetric top or Langmuir solution. We find critical values of the electric field beyond which the equilibrium is not possible. Values for the classical polarizability of rotating H- and He are reported. (author). 14 refs, 4 figs