Configuration-interaction-induced dynamic spin polarization of the ${\mathrm{Ar}}^{*}{\left(2p_{1∕2,3∕2}^{-1}4s_{1∕2}\right)}_{J=1}$ resonant Auger decay

Spin-resolved measurements of the ${\mathrm{Ar}}^{*}{\left(2p_{1∕2,3∕2}^{-1}4s_{1∕2}\right)}_{J=1}$ resonantly excited $L_{2,3}{M}_{2,3}{M}_{2,3}$ Auger decay have been performed. The low resolution Auger spectrum, which due to cancellation between different multiplet components should exhibit virtually zero dynamic spin polarization, reveals an unexpected nonvanishing polarization effect. Calculations within a relativistic distorted wave approximation explain this effect as configuration-interaction (CI) induced. The CI generates experimentally unresolved fine structure components with low and high total angular momentum, giving rise to asymmetric cases where the high $J$ part of certain multiplets is suppressed by internal selection rules for diagram lines. In this case, only the low $J$ components survive with no partner for spin-polarization cancellation.

Figure 1

(Color) Spin-resolved spectrum for the TSP [(a) and (b)] and DSP [(c) and (d)] for excitation with circularly and linearly polarized light, respectively. Full curves: 36 CSF-CI. Circles with errorbars: experimental data. Blue: partial intensities for spin up $\left(I^{+}\right)$. Red: partial intensities for spin down $\left(I^{-}\right)$. The degree of DSP and TSP for the unresolved group of lines is shown in the chart underneath. Open diamonds: 8 CSF-CI. Open squares: 36 CSF-CI. Filled circles: experimental data. The dashed lines in all figures separate spectra taken with different resolutions and, hence, retardation voltage.