Nucleon separation energies and shell indicators
Removing one neutron or proton from a specified ground-state nucleus costs S_n=B(A,Z)−B(A−1,Z) or S_p=B(A,Z)−B(A−1,Z−1).
Key knowledge
Removing one neutron or proton from a specified ground-state nucleus costs S_n=B(A,Z)−B(A−1,Z) or S_p=B(A,Z)−B(A−1,Z−1). Two-nucleon differences reduce some odd–even effects and changes across isotope/isotone sequences can reveal shell structure; a separation energy and total binding per nucleon answer different questions.
Values and equations
S_n=B(A,Z)−B(A−1,Z); S_p=B(A,Z)−B(A−1,Z−1); S_2n=B(A,Z)−B(A−2,Z)
- S_n,S_p,S_2n,B
- Separation and ground-state binding energies J
- A,Z
- Nucleon and proton counts
Conditions and scope
- Use the same bare-nucleus ground-state binding convention, include the actual residual state when excitation matters, and restrict indices to physically meaningful nuclei.
- A negative separation energy makes that separated channel energetically accessible; a positive value is not proof of stability against every other channel. Shell inference needs measured/systematically evaluated masses and uncertainties.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Introduction to Applied Nuclear Physics: chapter 1 (2012): Section 1.2.1, printed pages 6–7: one-neutron and one-proton binding differences. Introduction to Applied Nuclear Physics: chapter 5 (2012): Section 5.3.1B, printed pages 75–76: two-nucleon differences and observed shell discontinuities; no isotope data values are asserted.
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Entry details
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