@article {202,
	title = {Resonance effects on the two-photon emission from hydrogenic ions},
	journal = {Physical Review A (Atomic, Molecular, and Optical Physics)},
	volume = {79},
	number = {6},
	year = {2009},
	pages = {062504},
	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.},
	keywords = {bound states Dirac equation quantum electrodynamics radiative lifetimes two-photon processes},
	doi = {DOI: 10.1103/PhysRevA.79.062504},
	url = {http://link.aps.org/abstract/PRA/v79/e06250},
	author = {P Amaro and J P Santos and F. Parente and A. Surzhykov and P. Indelicato}
}
