## Abstract

A theoretical study of the all two-photon transitions from initial bound states with ni =2,3 in hydrogenic ions is presented. High-precision values of relativistic decay rates for ions with nuclear charge in the range 1≤Z≤92 are obtained through the use of finite basis sets for the Dirac equation constructed from B splines. We also report the spectral (energy) distributions of several resonant transitions, which exhibit interesting structures, such as zeros in the emission spectrum, indicating that two-photon emission is strongly suppressed at certain frequencies. We compare two different approaches (the line profile approach and the QED approach based on the analysis of the relativistic two-loop self-energy) to regularize the resonant contribution to the decay rate. Predictions for the pure two-photon contributions obtained in these approaches are found to be in good numerical agreement.

Original language | English |
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Article number | 062504 |

Journal | Physical Review A - Atomic, Molecular, and Optical Physics |

Volume | 79 |

Issue number | 6 |

DOIs | |

Publication status | Published - 9 Jun 2009 |