We demonstrate that the present superaccurate measurements of transition processes between atomic states in a hydrogen atom reached the limit of accuracy when transition the frequency could not be defined anymore in a unique way. This was predicted earlier and is due to the necessity to include the nonresonant corrections in the description of resonant processes. The observed spectral line profile becomes asymmetric, and it becomes impossible to extract the value of transition frequency from this profile in a unique way. Nonresonant corrections depend on the type of experiment and on the experimental arrangement. However, the line profile itself for any resonant process can be defined with any desired level of accuracy. A popular trend in the modern search for atomic frequency standards and atomic clocks is the search for transitions where the nonresonant corrections are negligible. In this paper we present closed expressions for the resonant photon scattering cross sections on ...

中文翻译：

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非共振校正对于描述原子光谱的重要性

我们证明了当无法以独特的方式定义频率跃迁时，氢原子中原子态之间跃迁过程的当前超精确测量值达到了精度极限。这是较早预测的，并且由于在谐振过程的描述中必须包括非谐振校正。观察到的谱线轮廓变得不对称，并且不可能以独特的方式从该轮廓中提取跃迁频率的值。非共振校正取决于实验的类型和实验的安排。但是，可以以任何所需的精度级别定义任何谐振过程的线路轮廓本身。在现代的原子频率标准和原子钟搜索中，一个流行的趋势是寻找可以忽略非共振校正的跃迁。在本文中，我们给出了谐振子在...上的光子散射截面的封闭表达式。