BIPOLARONS IN THE INTERMEDIATE COUPLING METHOD

The properties of pularons and bipolarons are studied by the intermedi ate coupling method, which takes electron-lattice coupling into accoun t. A Coulomb correlation in the electron motion is included. Where the Frohlich coupling constant is reduced, at alpha=5.7 a bipolaron deca ys suddenly from a self-trapped state into two delocalized polarons. A phase diagram is constructed for the region where the stable bipolaro n exists. These results are compared with those obtained by integratio n along trajectories. (C) 1997 American Institute of Physics.