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Mean potential of Bethe in the classical problem of calculating bulk electrostatic potentials in crystals

The mean potential of Bethe is discussed as a correction modifying direct potential series to translation‐invariant potentials in the bulk. As shown, this effect is associated with special periodic boundary conditions imposed at infinity. As a result, a unique potential solution independent of any particular choice of the unit cell arises. Based on this finding, the classical problem of asymmetry of Evjen's potentials and the problem of definition of the bulk Coulomb energy are readily resolved. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim )