Quantum electrodynamical (QED) calculations of ionization energies of the $1sndD$ states are performed for the helium atom. We reproduce the previously known relativistic and QED effects up to order $m{\alpha }^5$ and extend the theory by calculating the complete $m{\alpha }^6$ correction. The total contribution of the $m{\alpha }^6$ effects is shown to be much smaller than previously estimated, due to a large cancellation between the radiative and nonradiative parts of this correction. As a result of our calculations, we confirm the previously reported deviations between measured transition energies and theoretical predictions for the $nD\text{−}2S$ and $nD\text{−}2P$ transitions. Possible reasons for this discrepancy are analyzed.

中文翻译：

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氦气中第一态电离能的QED计算

分子电离能的量子电动力学（QED）计算 $\mathrm{1个}sñdd$对氦原子执行状态。我们按顺序重现以前已知的相对论和QED效应$米{\alpha }^5$ 并通过计算完整的 $米{\alpha }^6$更正。的总贡献$米{\alpha }^6$由于该校正的辐射部分和非辐射部分之间的抵消很大，因此显示出的影响比以前估计的要小得多。作为我们计算的结果，我们确认了先前报道的实测跃迁能量与理论预测值之间的偏差。$ñd\text{-}2\mathrm{小号}$ 和 $ñd\text{-}2P$过渡。分析了这种差异的可能原因。