Two-Photon Decays Reexamined: Cascade Contributions and Gauge Invariance

Abstract

The purpose of this paper is to calculate the two-photon decay rate corresponding to the two-photon transitions nS->1S and nD->1S in hydrogenlike ions with a low nuclear charge number Z (for principal quantum numbers n = 2,...,8. Numerical results are obtained within a nonrelativistic framework, and the results are found to scale approximately as (Z alpha)^6/n^3, where alpha is the fine-structure constant. We also attempt to clarify a number of subtle issues regarding the treatment of the coherent, quasi-simultaneous emission of the two photons as opposed to one-photon cascades. In particular, the gauge invariance of the decay rate is shown explicitly.

10 pages, LaTeX

References in corpus (6)

• Two-Loop Bethe Logarithms
• Logarithmic two-loop corrections to the Lamb shift in hydrogen
• Lamb Shift of 3P and 4P states and the determination of $\alpha$
• Radiative Corrections to One-Photon Decays of Hydrogenic Ions
• Asymptotic properties of self-energy coefficients
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• Two-photon atomic level widths at finite temperatures
• Separation of Transitions with Two Quantum Jumps from Cascades
• Two-photon approximation in the theory of the electron recombination in hydrogen
• Relativistic (Z alpha)^2-Corrections and Leading Quantum Electrodynamic Corrections to the Two-Photon Decay Rate of Ionic States
• Extension of the sum rule for the transition rates between multiplets to the multiphoton case
• Quantum Electrodynamics of Dicke States: Resonant One-Photon Exchange and Entangled Decay Rate
• Precision Rydberg State Spectroscopy with Slow Electrons and Proton Radius Puzzle
• Radiative corrections to the level width in the presence of magnetic field