The Electrical Conductivity of Metals

Abstract

IN the recent theories of metallic conduction the exchange of electrons between neighbouring atoms has perhaps not been sufficiently considered. The new quantum mechanics as applied to molecules has shown that, for distances of the order of those which separate the atoms in a crystal lattice, electrons go over from one atom to the other more than 1010 times per sec. Roughly, this frequency of interchange is a function of the nuclear charge, of the number of the electrons per atom, as well as of the average distance of the atomic neighbours (number of atoms per cell; temperature). These variables have been shown by K. F. Herzfeld (Phys. Review, vol. 29, p. 701; 1927) to be decisive in making an element a metallic conductor. An applied external field will favour the rate of exchange with the neighbours lying in the direction of the electric field, and cause a flow of electrons in one direction. For certain appropriate values of the atomic properties, super-conductivity may result.