We present extreme ultraviolet spectra of 3s3p–3s3d transitions in Fe¹⁴⁺ observed with a compact electron beam ion trap. The contributions of indirect excitation via a metastable state and resonant excitation are studied by observing the electron energy dependence of the spectra for the energy range of 60–210 eV. The results indicate that the 3s3d ¹D₂ level is directly excited from the 3s² ground state whereas the 3s3d ³D₃ level has a large contribution of the indirect excitation via the 3s3p ³P₂ metastable state. Comparisons with the theoretical excitation cross sections including MNn resonant excitations show good qualitative agreement with the experimental results for the electron energy dependent features.

中文翻译：

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用紧凑型电子束离子阱研究高电荷Fe离子的共振电子碰撞激发

我们用紧凑的电子束离子阱观察到了Fe ¹⁴⁺中3 s 3 p –3 s 3 d跃迁的极端紫外光谱。通过观察能量在60–210 eV范围内的光谱的电子能量依赖性，研究了通过亚稳态引起的间接激发和共振激发的作用。结果表明，3 s 3 d ¹ D ₂能级是从3 s ²基态直接激发的，而3 s 3 d ³ D ₃能级则是通过3 s间接激发的。 s 3 p ³ P ₂亚稳态。与包括MNn共振激发在内的理论激发截面的比较表明，与电子能量相关特征的实验结果具有很好的定性一致性。