Post on 12-Feb-2022
Alpha Particle Structure of Nucleus
Jinesh Kallunkathariyil
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Nuclear Structure Theories
1. Large binding energy
2. Stable isotopes
3. Abundance
4. Naturally occurring radioactive series decay to the stable
end product Pb with Z=82 in three isotopic forms having N=126 for one of them.
Experimental evidences for the existence of magic numbers
2, 8, 20, 28, 50, 82, and 126
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5. Neutron absorbing cross section is very low 7. First excited states is at higher energies 8. Electric quadrupole moment of magic numbered nuclei is near zero indicating the spherical symmetry of nucleus for closed shells. 9. High energy of alpha or beta particles emitted
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History
โJust because you see alpha particles coming out of nucleus, you should not necessarily conclude that inside they exist as such โ
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Bethe and Bacher (1936)
Ernest Rutherford (1899) Alpha particle decay
Wefelmeier (1937) Wheeler (1937) Von Weizsacker (1938)
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Hafstad and Teller (1938)
Martin Freer (2010)
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Semi-classical Microscopic Approach to the Liquid drop model
Zbigniew Sosin (http://arxiv.org/abs/1304.2846)
12C
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16O
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20Ne
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24Mg
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28Si
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40Ca
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56Ni
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Binding energy and number of bonds
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60Zn
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First Approximation
Binding energy of alpha particle (4He),
๐๐ผ = 28.296๐๐๐
๐ถ12 = 3๐ผ ?
๐ต ๐ถ12 = 92.163๐๐๐
3๐ผ = 84.888๐๐๐ < ๐ต ๐ถ12
๐ต = ๐๐ผ ร ๐๐ผ + ๐๐ ร ๐๐ผโ๐ผ
๐๐ผโ๐ผ = 2.425๐๐๐
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๐ต = ๐๐ผ ร ๐๐ผ + ๐๐ ร ๐๐ผโ๐ผ
From Zn, Betheโs prediction changes
Zn
Ge
Zr
Ni
Binding energy 1 center ฮฑ bond energy = ๐. ๐๐๐ ๐ด๐๐ฝ
2 center ฮฑ bond energy = ๐ ร ๐. ๐๐๐ ๐ด๐๐ฝ = ๐. ๐๐๐๐ด๐๐ฝ
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Bond length and bond energy
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Z=N=odd
๐4๐+2 = ๐4๐ + 12.498๐๐๐
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Structure of nuclei heavier than Sn
Color lines are the experimental binding energy for all nuclei. Same color shows the isotopes of same nuclei
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Structure of nuclei heavier than Sn
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Alpha Particle structure of nuclei
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Alpha Particle structure of nuclei?
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Fission Fragment distribution
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More evidences!!
Density distribution
Giant Dipole Resonance (GDR)
Results and Conclusion
โข Structural change from Zn is the reason for the abundance of Iron peak elements in the Universe
โข Alpha particle need high energy to overcome the coulomb energy of balloon like surface to enter inside
โข Supernova explosion
โข Nuclear fission
โข Asymmetric fission
โข Symmetric fission
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Thank youโฆ
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