Defect and Binding Energy

For all stable nuclei, it is found that the mass of the nucleus is less than the sum of the masses of its constituent nucleons, considered independently. This difference is known as the mass defect. For a nucleus of mass number A, containing Z protons and N neutrons, the mass defect may be defined by the relation 

By the Einstein mass-energy equivalence principle, the mass defect is the mass equivalent of the work done by the nuclear force in bringing the nucleons together to form the nucleus or, alternatively, of the loss of mutual potential energy of the nucleons as a result of their accretion. The energy 

Another important parameter is the binding energy per nucleon for the nucleus, which is obtained by dividing by the number of nucleons  

This quantity represents the average energy which has to be supplied to remove a nucleon from the nucleus, or, alternatively, the average energy given to the nucleus when a free proton or neutron is absorbed into it. 

Some useful conversion factors involving energy and mass units are summarized in Table 1.2 for a more detailed listing of fundamental constants and conversion factors see Appendix (Tables A.l and A.2). 

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What is the relationship between mass defect and binding energy ... 

Calculate the mass defect and binding energy of lithium-7. The mass of lithium-7 is 7.016003 amu. 

TABLE 21.7 Mass Defects and Binding Energies for Three Nuclei... 

R.W. Balluffi. Vacancy defect mobilities and binding energies obtained from annealing studies. J. Nucl. Mats., 69-70 240-263, 1978. 

Surface defects always involve local variations in electronic states and binding energies. Therefore, surface defects are crucial in processes such as adsorption, nucleation, and surface reactions. For example, the step of a screw dislocation can eliminate the nucleation barrier for crystal growth. 

Obtain the mass defect (in amu) and binding energy (in MeV) for the flNi nucleus. What is the binding energy (in MeV) per nucleon See Table 21.3. 

Table 4.16 Calculated lifetimes r and binding energies of positions trapped in the core region of a dislocation line and in defects associated with dislocation [112]...

Table 4.3 Calculated defect complex binding energies, Eh, and acceptor transition energy levels (all in eV) in ZnO resulting from codoping acceptors (N or Vzn) with donor (Fq) or isovalent (Mg, Be) atoms.

High-mass resolution is needed to separate mass interferences of molecular and atom ions. Because of the mass defect of the binding energy of the nucleus, atomic ions have a slightly smaller mass than the corresponding molecular ions. To observe this typical mass resolutions between 5000 and 10000 are necessary. 

In addition, for two coaxial armchair tubules, estimates for the translational and rotational energy barriers (of 0.23 meV/atom and 0.52 meV/atom, respectively) vvere obtained, suggesting significant translational and rotational interlayer mobility of ideal tubules at room temperature[16,17]. Of course, constraints associated with the cap structure and with defects on the tubules would be expected to restrict these motions. The detailed band calculations for various interplanar geometries for the two coaxial armchair tubules basically confirm the tight binding results mentioned above[16,17]. 

Beta radiation Electron emission from unstable nuclei, 26,30,528 Binary molecular compound, 41-42,190 Binding energy Energy equivalent of the mass defect measure of nuclear stability, 522,523 Bismuth (m) sulfide, 540 Blassie, Michael, 629 Blind staggers, 574 Blister copper, 539 Blood alcohol concentrations, 43t Body-centered cubic cell (BCC) A cubic unit cell with an atom at each comer and one at the center, 246 Bohrmodd Model of the hydrogen atom... 

Nuclear fusion processes derive energy from the formation of low-mass nuclei, which have a different binding energy. Fusion of two nuclear particles produces a new nucleus that is lighter in mass than the masses of the two fusing particles. This mass defect is then interchangeable in energy via Einstein s equation E = me2. Specifically, the formation of an He nucleus from two protons and two neutrons would be expected to have mass ... 

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