@article {707,
	title = {Two-photon absorption of few-electron heavy ions},
	journal = {Physical Review A},
	volume = {84},
	year = {2011},
	note = {<p>Copyright (C) 2010 The American Physical SocietyPlease report any problems to prola@aps.orgPRAWebpage CFA-FCTUNL</p>
},
	pages = {022511},
	publisher = {American Physical Society},
	abstract = {<p>The two-photon absorption of few-electron ions has been studied by using second-order perturbation theory and Dirac{\textquoteright}s relativistic equation. Within this framework, the general expressions for the excitation cross sections and rates are derived including a full account of the higher-order multipole terms in the expansion of the electron-photon interaction. While these expressions can be applied to any ion, independent of its particular shell structure, detailed computations are carried out for the two-photon absorption of hydrogen-, helium-, and berylliumlike ions and are compared with the available theoretical and experimental data. The importance of relativistic and nondipole effects in the analysis and computation of induced two-photon transitions is pointed out. Moreover, we discuss the potential of these transitions for atomic parity-violation studies in the high-Z domain.</p>
},
	keywords = {PACS: 32.90.+a, 32.80.Rm, 32.80.Wr, 31.10.+z},
	url = {http://link.aps.org/doi/10.1103/PhysRevA.84.022511},
	author = {A. Surzhykov and P. Indelicato and J P Santos and P Amaro and Th St{\"o}hlker and S. Fritzsche}
}
