The Auger Resonances

As discussed earlier the spectral representation of the matrix propagator 

13 where the distances narrow as we approach a = 0.85 and then increase again. This quasi-stable value in the alpha trajectory has been taken as the best estimate of the resonant Auger pole form this decoupling /42/. The values for the energies and widths of the Be+ (Is-1) 2S Auger resonance from these calculations along with experimental and other theoretical results are collected in table VII. 

Electron Propagator with Siegert Boundary condition /24/ 125.47 0.02 

Quasiparticle Second order Dilated Electron Propagator /42/ 124.98 0.05 

Our results therefore seem to indicate that the extra effort in implementing the diagonal 2ph-TDA approximation for the dilated electron propagator calculations is unwarranted, at least from the experience gained in this and some other investigations /40,41,44,45/. 

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Figure 10. Theta trajectories for the Be+ (Is-1) Auger pole from the zeroth (bi-variational SCF), second order ( 3), quasiparticle second order (Ej), diagonal Sph-TDA ( 3pA TIM) and quasiparticle diagonal Sph-TDA (E3ph TDA) decouplings of the dilated electron propagator. The disparity between the theta trajectories for the SCF and propagator poles makes apparent the magnitude of correlation and relaxation effects attending the Auger resonance formation.

Figure 11. Same as fig. 10 but without the zeroth order decoupling. The diagonal Sph-TDA results predict higher energy and smaller width for the Auger resonance. A magnified version of the second order (E3), and the quasiparticle second order (E3 trajectories is displayed in the inset.

Figure IS. a trajectory for 8 = 0.11 radians for the quasiparticle diagonal Zpk-TDA 2ph-TDA) dec0Uplxfig, The distances narrow as a = 0.85 is approached and then increase again. The quasi-stable value of the pole at this alpha value is therefore taken to be the best estimate of the energy and width of the Auger resonance from this decoupling.

Oliphant and Moon theoretically considered the possibility of electron emission by resonance ionization of metastable atoms near a metal surface. Shekter [122] investigated the Auger-neutralization of ions on a metal surface. Hagstrum [124, 125] carried out an generalized analysis of metastable atoms with a metal surface. 

Fig. 15. Angle-integrated photoelectron energy distribution curves of uranium in the region of the giant 5 d -> 5 f resonance (90 eV < hv < 108 eV). The 5 f intensity at Ep is suppressed by more than a factor of 30 at the 5 ds/2 threshold (see the spectra for hv = 92 and 94 eV) and resonantly enhanced above threshold (see, e.g., the spectrum for hv = 99 e V). At an initial energy 2.3eV below Ep a new satellite structure is observed which is resonantly enhanced at the 5 d5/2 and 5 ds onsets. At threshold the satellite coincides with the Auger electron spectrum, which moves to apparently larger initial energies with increasing photon energy (from Ref. 67)...

In addition, the observed width of an Auger line is also affected by the spectrometer resolution. However, the bandpass of the incident radiation which produces the initial state for the Auger decay does not play a role, unlike in the case of the width of an observed photoline. (This statement only holds for the two-step model of inner-shell ionization and subsequent Auger decay. In the vicinity of the inner-shell ionization threshold it significantly fails due to postcollision interaction (Section 5.5) and the resonant Raman Auger effect (Section 5.1.2.1).) Hence, Auger transitions often appear in the spectra of ejected electrons as lines much sharper than the corresponding photolines. 

Auger Resonant Raman Processes Effects of the Partial Density of Unoccupied Electronic States on Resonant KLL Auger Spectra in... 

AUGER RESONANT RAMAN PROCESSES EFFECTS OF THE PARTIAL DENSITY OF UNOCCUPIED ELECTRONIC STATES ON RESONANT KLL AUGER SPECTRA IN Cu AND Ni METALS... 

Characterization of Shape and Auger Resonances using The Dilated One Electron Propagator Method. 

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