We report on ${\mathrm{C}}^{3+}(1s2\ell 2{\ell }^{\prime }{}^{2S+1}\mathrm{L})$-resolved cross sections of electron capture in collisions of swift ${\mathrm{C}}^{4+}(1s2s{}^3\mathrm{S})$ ions with helium and hydrogen. The study focuses on the formation of doubly excited triply open-shell ${\mathrm{C}}^{3+}(1s2s2p){}^4\mathrm{P}$ and ${{}^2\mathrm{P}}_{\pm }$ states with emphasis on the ratio $R$ of their cross sections as a measure of spin statistics. Using zero-degree Auger projectile spectroscopy and a three-electron close-coupling semiclassical approach, we resolve a long-standing puzzle and controversy on the value of $R$ and on the effect of cascades, to clarify the underlying physics. The present results invalidate the frozen core approximation generally used in the past when considering electron capture in multielectron multi-open-shell quantum systems. A distinctive screening effect due to the Pauli exclusion principle (Pauli shielding) is proposed to account for the value of $R$, consistent with our findings.

中文翻译：

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多电子多开壳动力原子系统中的保利屏蔽和自旋统计的分解

我们报告 ${\mathrm{C}}^{3+}（\mathrm{1个}s2\ell 2{\ell }^{\prime }{}^{2\mathrm{小号}+\mathrm{1个}}\mathrm{大号}）$碰撞中电子捕获的高分辨截面 ${\mathrm{C}}^{4+}（\mathrm{1个}s2s{}^3\mathrm{小号}）$与氦和氢离子。该研究的重点是双激发三重开壳的形成${\mathrm{C}}^{3+}（\mathrm{1个}s2s2p）{}^4\mathrm{P}$ 和 ${{}^2\mathrm{P}}_{\pm }$ 强调比例的国家 $\mathrm{[R}$的横截面作为自旋统计的度量。使用零度俄歇射弹光谱学和三电子紧密耦合半经典方法，我们解决了长期存在的难题和关于$\mathrm{[R}$并通过级联效应来阐明基本物理原理。当考虑在多电子多开壳量子系统中捕获电子时，当前结果使过去通常使用的冻结核近似无效。建议使用保利排除原理（保利屏蔽）产生独特的屏蔽效果，以说明$\mathrm{[R}$，与我们的发现一致。