https://doi.org/10.1351/goldbook.08811
Theory describing the electronic structure of a solid in terms of energy intervals, called energy bands that are allowed or forbidden for occupation by electrons.
Notes:
- The energy band theory stems from the solution of the Schrödinger equation for electron waves moving in a periodic crystal lattice where, due to the wave diffractions, only some directions of the wave propagation characterized by the wave vector (so-called
- When several atoms form a molecule, their atomic orbitals are transformed into a set of discrete bonding and antibonding molecular orbitals (energy levels), the number of which is proportional to the number of involved atoms. The energy levels that an electron is allowed to occupy are separated by energy intervals without any energy levels that an electron can occupy. If many atoms are linked together to form a lattice, the number of energy levels that the electrons are allowed to occupy becomes exceedingly large. Among these energy levels, large subsets of energy levels exist in which energy differences between individual levels are so small that they may be regarded as a quasi-continuum (individual energy levels are of no importance). The subset of energy levels that can be occupied by electrons is named allowed energy bands. The allowed bands are separated by energy intervals that electrons cannot occupy, which are called forbidden bands or energy bandgaps.