title: Free electron
text: # Free electron
  
  Free electron in physics may refer to:
  
  * Electron, as a free particle
  * Solvated electron
  * Charge carrier, as carriers of electric charge
  * Valence electron, as an outer shell electron that is associated with an atom
  * Valence and conduction bands, as a conduction band electron relative to the electronic band structure of a solid
  * Fermi gas, as a particle of a non-interacting electron gas
  * Free electron model, as a particle in the Drude-Sommerfeld model of metals
  * Free-electron laser, as a particle in the electron beam
  