$LS/LSJ$ 混合耦合框架用于实验未分辨多重态与孤立精细结构的俄歇角分布
Strong Angular-Momentum-Coupling Dependence of Atomic Decay Angular Distributions in a Hybrid $\mathbf{LS/LSJ}$ Framework
- University of Crete（克里特大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
提出混合 $LS/LSJ$ 耦合框架，处理孤立精细结构多重态，应用于 $1s2s2p\\,^4\\!P_J$ 流形，揭示俄歇角分布各向异性抑制与反转，显著改善与实验数据的一致性。
AI中文摘要：
我们提出了一个混合 $LS/LSJ$ 耦合框架，用于处理满足条件 $\Delta E_\text{int}\sim\hbar/\tau_\text{int} \gg\Delta E_\text{FS}\gg\Gamma$ 的状态多重态，其中 $\tau_\text{int}$ 是碰撞相互作用时间，$\Delta E_\text{FS}$ 是精细结构分裂，$\Gamma$ 是自然宽度。在该条件下，碰撞相互作用相对于精细结构演化是快的，而各个 $J$ 能级在其自然宽度尺度上是良好孤立的。因此，所产生的多重态的排列（alignment）在 $LS$ 耦合下描述，然后在其后续衰变之前投影到各个精细结构 $J$ 能级上，衰变过程由 $LSJ$ 耦合描述。将该框架应用于多开壳层 $1s2s2p\\,^4\\!P_J$ 流形，该流形紧密满足这些条件，混合处理揭示了相对于传统纯 $LS$ 处理的俄歇角分布各向异性的强烈抑制和反转。在使用相同的 $LS$ 产生截面的同时，它显著改善了与绝对实验数据的一致性。因此，该混合 $LS/LSJ$ 框架为具有孤立精细结构能级的状态多重态提供了恰当的处理方法，因为它保留了传统纯 $LS$ 处理所缺失的 $J$ 依赖衰变动力学。
英文摘要：
State production and its subsequent decay can each require a different angular-momentum coupling treatment. Although long recognized, this distinction is often overlooked in the two-step model, where $LS$ coupling is traditionally applied to both production and decay ($LS/LS$), even when the decay requires $LSJ$ coupling. We introduce a hybrid $LS/LSJ$ formulation that uses established angular-momentum recoupling theory to project the initial $LS$ alignment onto the fine-structure $J$ states, evaluates their decay in $LSJ$ coupling, and, for well-separated $J$ levels, sums their contributions incoherently. The $1s2s2p\,{}^{4}\!P_J$ manifold produced by single-electron capture in $\mathrm{C}^{4+}(1s2s\,{}^{3}\!S)+\mathrm{He}$ collisions provides a good test case, with $M_L$-resolved theoretical production cross sections and absolute measurements of the Auger single-differential cross section available. Using the same $LS$ production cross sections in both treatments, we find that the hybrid $LS/LSJ$ treatment strongly suppresses and can even invert the Auger anisotropy relative to the traditional $LS/LS$ treatment, substantially improving agreement with the measurements. Such an incoherent hybrid formulation provides the appropriate framework when $LS$ coupling governs the initial interaction dynamics while well-separated fine-structure levels require an $LSJ$ description of the decay.
