Solids as Supergiant Molecules: LCAO

Summary

A one–dimensional periodic model of coupled pendulums is introduced, which, on the one hand, reduces to that of ionic coupled oscillations, and on the other, is mathematically equivalent to the electronic motion in the framework of the LCAO. The latter, depending on its parameters, can describe one–dimensional “metals,” “ionic solids,” “molecular solids,” “elemental semiconductors,” and “compound semiconductors.” Furthermore, important concepts, such as band and gaps, effective masses, valence and conduction bands, and gap size, Eg, are introduced.