Bipolaron States of Electrons and Magnetic Properties of Metal-Ammonia Systems

A theoretical approach is proposed to describe the concentration and temperature dependences of the static magnetic susceptibility of a metal–ammonia system. A mechanism is also suggested to explain the transition of the system from the paramagnetic to the diamagnetic state. The theory is based on the assumption that both single-particle (polarons) and two-electron bound singlet formations of the bipolaron type exist in the system. It is shown that diamagnetism is due to the electron orbital motion and to the relative motion of the quasiparticles.