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Binding energy is the energy required to disassemble a whole system into separate parts. A bound system typically has a lower potential energy than the sum of its constituent parts; this is what keeps the system together. Often this means that energy is released upon the creation of a bound state. This definition corresponds to a ''positive'' binding energy. == General idea == In general, binding energy represents the mechanical work that must be done against the forces which hold an object together, disassembling the object into component parts separated by sufficient distance that further separation requires negligible additional work. At the atomic level the atomic binding energy of the atom derives from electromagnetic interaction and is the energy required to disassemble an atom into free electrons and a nucleus.〔(【引用サイトリンク】title=Nuclear Power Binding Energy )〕 Electron binding energy is a measure of the energy required to free electrons from their atomic orbits. This is more commonly known as ionization energy. At the molecular level, bond energy and bond-dissociation energy are measures of the binding energy between the atoms in a chemical bond. At the nuclear level, binding energy is also equal to the energy liberated when a nucleus is created from other nucleons or nuclei.〔''Britannica Online Encyclopaedia'' - "nuclear binding energy". Accessed 8 September 2010. http://www.britannica.com/EBchecked/topic/65615/binding-energy〕〔Nuclear Engineering - "Binding Energy". Bill Garland, McMaster University. Accessed 8 September 2010. http://www.nuceng.ca/igna/binding_energy.htm〕 This nuclear binding energy (binding energy of nucleons into a nuclide) is derived from the nuclear force (residual strong interaction) and is the energy required to disassemble a nucleus into the same number of free, unbound neutrons and protons it is composed of, so that the nucleons are far/distant enough from each other so that the nuclear force can no longer cause the particles to interact.〔''Atomic Alchemy: Nuclear Processes'' - "Binding Energy". (About ). Accessed 7 September 2010. http://library.thinkquest.org/17940/texts/binding_energy/binding_energy.html〕 Mass excess is a related concept which compares the mass number of a nucleus with its true measured mass. In astrophysics, the gravitational binding energy of a celestial body is the energy required to expand the material to infinity. In bound systems, if the binding energy is removed from the system, it must be subtracted from the mass of the unbound system, simply because this energy ''has'' mass. Thus, if energy is removed (or emitted) from the system at the time it is bound, the loss of energy from the system will also result in the loss of the mass of the energy, from the system.〔''HyperPhysics'' - "Nuclear Binding Energy". ''C.R. Nave'', Georgia State University. Accessed 7 September 2010. http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.html〕 System mass is not conserved in this process because the system is "open" (i.e., is not an isolated system to mass or energy input or loss) during the binding process. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Binding energy」の詳細全文を読む スポンサード リンク
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