Nuclear electromagnetic multipoles and internal conversion
For an electromagnetic nuclear transition with good angular momentum and parity, a single emitted photon has multipolarity L≥1 satisfying |J_i−J_f|≤L≤J_i+J_f.
Key knowledge
For an electromagnetic nuclear transition with good angular momentum and parity, a single emitted photon has multipolarity L≥1 satisfying |J_i−J_f|≤L≤J_i+J_f. An electric E L transition has parity ratio π_f/π_i=(−1)^L; magnetic M L has (−1)^(L+1). Consequently a 0→0 transition cannot emit one photon. Internal conversion can instead transfer nuclear transition energy to a bound atomic electron, ejecting it without changing nuclear A or Z.
Values and equations
L≥1; |J_i−J_f|≤L≤J_i+J_f; π_f/π_i=(−1)^L for E L, (−1)^(L+1) for M L
- L,J_i,J_f
- Photon multipolarity and initial/final nuclear angular-momentum quantum numbers
- π_i,π_f
- Nuclear parity signs
- E L,M L
- Electric and magnetic multipole labels
Conditions and scope
- J_i,J_f are angular-momentum quantum numbers and π_i,π_f=±1. These are selection constraints on the electromagnetic channel, not guaranteed nonzero transition matrix elements or absolute rates.
- Recoil and binding energies enter electron/photon energies. Internal conversion is nuclear de-excitation through an atomic electron, not beta emission; the ion's electron population changes even though nuclear A/Z do not.
Sources · 1
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 7 (2012): Sections 7.1.3–7.1.4, printed pages 97–99: angular/parity multipole constraints, electron conversion and the no-single-photon 0→0 limitation. Crude universal multipole-strength ratios and a naive Δl=±1 rule are not adopted.
2026-10-10 · Independent AI editorial review: All 136 unique authored Physics compact statements, all hypotheses and displayed equations/variable/units tables, all 192 Physics-origin semantic links, exact 165 author inspection matrix and mapped retained conceptual claims have been independently read. Three Physics-tagged Measurement realization records are delegated to root Measurement review. Scientific source verification combines exact author section inspection with independent whole compact-content/semantic review and targeted primary rechecks recorded below; it does not claim each full source body was independently reread. Independent AI editorial review is not human specialist certification or experimental replication. Field inventory is approved after independently reviewing the two added source-inspected band-construction methods. Receipt: physics-independent-content-inventory-review.1.
Entry details
Permanent link to this entry ↗- Record identity
- physics-nuclear-gamma-selection
- Revision
- university-core.1
- Structured reference record
- University core expansion