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Electron binding energy; Ionization energy Electron binding energy, more commonly known as ionization energy, [3] is a measure of the energy required to free an electron from its atomic orbital or from a solid. The electron binding energy derives from the electromagnetic interaction of the electron with the nucleus and the other electrons of ...
The right graph shows the energy levels as a function of the spacing between atoms. When the atoms are far apart (right side of graph) the eigenstates are the atomic orbitals of carbon. When the atoms come close enough (left side) that the orbitals begin to overlap, they hybridize into molecular orbitals with different energies.
In graphs of the electronic band structure of solids, the band gap refers to the energy difference (often expressed in electronvolts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote an electron from the valence band to the conduction band.
The dispersion relations show conics of the free-electron energy dispersion parabolas for all possible reciprocal lattice vectors. This results in a very complicated set intersecting of curves when the dispersion relations are calculated because there is a large number of possible angles between evaluation trajectories, first and higher order ...
In another example, the electron binding energy refers to the minimum amount of energy required to remove an electron from the dicarboxylate dianion − O 2 C(CH 2) 8 CO − 2. The graph to the right shows the binding energy for electrons in different shells in neutral atoms.
The band gap (usually given the symbol ) gives the energy difference between the lower edge of the conduction band and the upper edge of the valence band. Each semiconductor has different electron affinity and band gap values. For semiconductor alloys it may be necessary to use Vegard's law to calculate these values.
The vertical axis of the band diagram represents the energy of an electron, which includes both kinetic and potential energy. The horizontal axis represents position, often not being drawn to scale. Note that the Heisenberg uncertainty principle prevents the band diagram from being drawn with a high positional resolution, since the band diagram ...
Energy vs. crystal momentum for a semiconductor with a direct band gap, showing that an electron can shift from the highest-energy state in the valence band (red) to the lowest-energy state in the conduction band (green) without a change in crystal momentum. Depicted is a transition in which a photon excites an electron from the valence band to ...