Negative-continuum effects on the two-photon decay rates of hydrogenlike ions

摘要: Two-photon decay of hydrogenlike ions is studied within the framework second-order perturbation theory, based on relativistic Dirac's equation. Special attention paid to effects arising from summation over negative-energy (intermediate virtual) states that occur in such a framework. In order investigate role these states, detailed calculations have been carried out for $2{s}_{1/2}\ensuremath{\rightarrow}1{s}_{1/2}$ and $2{p}_{1/2}\ensuremath{\rightarrow}1{s}_{1/2}$ transitions neutral hydrogen H as well xenon ${\text{Xe}}^{53+}$ uranium ${\text{U}}^{91+}$ ions. We found correct evaluation total energy-differential rates, part spectrum should be properly taken into account both high-$Z$ low-$Z$ atomic systems.