Aharonov-Casher effect for particles of arbitrary spin

The Aharonov-Casher (AC) effect for the quantum motion of a neutral magneti zed particle in an electric field is believed to be a topological effect cl osely related to the well-known Aharonov-Bohm (AB) effect. We study its dep endence on the spin of the particle involved. Duality of the AB and AC effe cts is demonstrated to exist only for two extreme spin (and magnetic-moment ) projections. A classical consideration confirms this conclusion. The moti on of a classical magnetized particle with generally oriented magnetic mome nt in the AC field appears to be subjected to both forces and torques. Only for two special orientations of the magnetic moment (same as in the quantu m case) is the motion in question effectively free and similar to the AB mo tion of a charged particle. Thus, the AC effect is not really topological. The presence of higher multipoles totally destroys possible AB-AC duality.