Electron shells in over-critical external fields

Berndt Müller, Johann Rafelski, Walter Greiner

Research output: Contribution to journalArticlepeer-review

111 Scopus citations


When the charge of a nucleus exceeds Z=Zcr≈ 164-172 the energy of the 1 s-electron level is lowered beyond the critical value of -mec2. Then this bound level is degenerated with negative energy continuum solutions of the Dirac equation and becomes a resonance, whose shape varies and is approximately of Breit-Wigner type for Z-Zcr≳5. The physical meaning of this resonance can be understood most easily if the 1 s-level is unoccupied (K-hole). In this case a positron may escape if Z>Zcr, a process, that can be interpreted as auto-ionization of the positron. This fundamentally new process of quantum electrodynamics of strong fields can be tested experimentally by scattering very heavy ions (Z≧80) on each other since in such collisions superheavy electronic molecules occur (superheavy quasimolecules).

Original languageEnglish (US)
Pages (from-to)62-77
Number of pages16
JournalZeitschrift für Physik
Issue number1
StatePublished - Feb 1972

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • General Physics and Astronomy


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