CHAINPLOT: A Teaching Tool to Demonstrate Vibrations of Atoms on a Chain   and the Cautionary Tale of a Fundamental Error Propagated Over the Last 63   Years
  Simulation of the so-called monatomic and diatomic chains by the computer program CHAINPLOT is described. The simulation provides useful teaching material for undergraduate condensed matter physics lecture courses, and has revealed that for the last 63 years a fundamental description of the actual atomic motions has been copied in the literature, despite being incorrect or at least misleading.. 
Anthony Michael Glazer
physics.ed-ph