In quantum mechanics, the particle in a one-dimensional lattice is a problem that occurs in the model of a periodic crystal lattice. The Kronig-Penney model  is a simplified model for an electron in a one-dimensional periodic potential. This Topic "Kronig Penney Model" is from Band Theory of Solids from Solid State Physics. Here I go over the results of the kronig-penney model: The E/k (energy/ momentum) diagram. The KP model is a single-electron problem.