Figure 4.

(a) Photon energy dependence of the relative intensity $R\left(\omega \right)$, see Equation (4), of the emission from the $B_2$ state ($I_p$) at $k_{\left|\right|}=1.780$ Å${}^{-1}$ and $A_2$ state ($I_s$) at $k_{\left|\right|}=1.633$ Å${}^{-1}$ for the polarization angle $\varphi ={78}^{\circ }$ (4.3% of p and 95.7% of s polarization). Both initial states are located at about 0.4 eV above the DP. Full circles show the measurements of Ref. [18] (digitized from Figure 5 in that work). (b) Calculated constant initial state spectra $I_s\left(\omega \right)$ (black) and $I_p\left(\omega \right)$ (red). (c) Logarithmized intensities ${log}_{10}{I}_s\left(\omega \right)$ (black) and ${log}_{10}{I}_p\left(\omega \right)$ (red). (d) Dwell time $\tau \left(E\right)$: The probability to find the electron in the LEED state within a layer between $z=-2$ and 2 a.u., see Figure 1. The final state energy E is relative to the DP. (e) Electron transmission $T\left(E\right)$ for $k_{\left|\right|}=1.633$ Å${}^{-1}$ (black) and $k_{\left|\right|}=1.780$ Å${}^{-1}$ (red). To facilitate the comparison, the E range in graphs (d) and (e) is shifted by 0.4 eV (initial state energy) relative to the $\hslash \omega$ range in graph (c).