 Quantum mechanics of electrons in crystal lattices by R. de L. Kronig and W. G. Penney

By R. de L. Kronig and W. G. Penney. Proceedings of the Royal Society A 130, 499–513. Section 1, pp. 500–503, derives the periodic rectangular-barrier model, its narrow-barrier limit and the allowed/forbidden energy intervals; the printed received date is 13 November 1930.

Original paper scan: www.physics.umd.edu/courses/Phys402/AnlageFall21/Kronig-Penney%20Model%201931-Quantum%20mechanics%20of%20electrons%20in%20crystal.pdf