<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Surzhykov, A.</style></author><author><style face="normal" font="default" size="100%">Volotka, A.</style></author><author><style face="normal" font="default" size="100%">Fratini, F.</style></author><author><style face="normal" font="default" size="100%">Santos, J. P.</style></author><author><style face="normal" font="default" size="100%">Indelicato, P.</style></author><author><style face="normal" font="default" size="100%">Plunien, G.</style></author><author><style face="normal" font="default" size="100%">Stöhlker, Th</style></author><author><style face="normal" font="default" size="100%">Fritzsche, S.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Angular correlations in the two-photon decay of heliumlike heavy ions</style></title><secondary-title><style face="normal" font="default" size="100%">Physical Review A</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">31.10.+z, 31.30.jc, 32.80.Wr</style></keyword><keyword><style  face="normal" font="default" size="100%">PACS:</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://link.aps.org/doi/10.1103/PhysRevA.81.042510</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">4</style></number><publisher><style face="normal" font="default" size="100%">American Physical Society</style></publisher><volume><style face="normal" font="default" size="100%">81</style></volume><pages><style face="normal" font="default" size="100%">042510</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The two-photon decay of heavy, helium-like ions is investigated based on second-order perturbation theory and Dirac’s relativistic equation. Special attention has been paid to the angular emission of the two photons (i.e., how the angular correlation function depends on the shell structure of the ions in their initial and final states). Moreover, the effects from the (electric and magnetic) nondipole terms in the expansion of the electron-photon interaction are discussed. Detailed calculations have been carried out for the two-photon decay of the 1s2s1S0, 1s2s3S1, and 1s2p3P0 states of helium-like Xe52+, Au77+, and U90+ ions.</style></abstract><notes><style face="normal" font="default" size="100%">Copyright (C) 2010 The American Physical SocietyPlease report any problems to prola@aps.orgPRA</style></notes></record></records></xml>