Free Electron Gas Model
In the free electron model the valence electrons roam freely (zero force) inside the metal but find a confining potential step at the boundary of the metal. In the system's ground state, states with energy less than the Fermi Level are occupied, and states above the Fermi Level are not occupied. The energy required to liberate an electron in the Fermi Level is the work function. If, as in the diagram right, we define the Fermi Energy from the bottom of the well, the results reported in the Wiki page Fermi energy are applicable. However, usually the Fermi energy is referenced to energy zero: that of the lowest energy electron free of the metal. In that case the Fermi energy would have a negative value (i.e., the Fermi Level lies below those of escaped electrons) (but see below).
Read more about this topic: Work Function
Famous quotes containing the words free, gas and/or model:
“I am always glad to think that my education was, for the most part, informal, and had not the slightest reference to a future business career. It left me free and untrammeled to approach my business problems without the limiting influence of specific training.”
—Alice Foote MacDougall (1867–1945)
“Man moves in all modes, by legs of horses, by wings of winds, by steam, by gas of balloon, by electricity, and stands on tiptoe threatening to hunt the eagle in his own element.”
—Ralph Waldo Emerson (1803–1882)
“... if we look around us in social life and note down who are the faithful wives, the most patient and careful mothers, the most exemplary housekeepers, the model sisters, the wisest philanthropists, and the women of the most social influence, we will have to admit that most frequently they are women of cultivated minds, without which even warm hearts and good intentions are but partial influences.”
—Mrs. H. O. Ward (1824–1899)