Coster-Kronig decay/electron

Since the energy of the electron in the Coster-Kronig decay is high up in the continuum (cf. Fig. 2) one can argue that the choice of basis set is not very critical and that neglecting the attraction of the extra hole is compensated for by neglecting the repulsion from coupling the electron-hole excitation to P. 

Coster-Kronig decay Tliis decay process is a special Auger decay in which the original vacancy is transferred to a higher subshell of the same shell. Auger and Coster-Kronig transitions are (essentially) two-electron processes and cause the emission of electrons with characteristic energies. 

A particularly interesting Auger process is the xenon L2-L3N4 Coster-Kronig decay excited by photons close to threshold. The emitted L2-L3N4 Coster-Kronig electron has a low electron energy of 228.4 eV, which makes it sensitive to electron-electron interactions. Close to threshold the photoelectron recedes only slowly from the atom and is still in the vicinity of the... 

Fig. 24a-i. One-electron level pictures and self-energy diagrams for dynamic relaxation of 4 s and 4p holes, (a)—(c) and (f, g) describe giant Coster-Kronig fluctuation (full plus dashed arrows) and decay processes (full arrows) while (d, e) and (f,) (h, i) correspondingly describe Coster-Kronig fluctuations and decay processes... 

An accurate knowledge of the individual rates of vacancy decay is interesting in several fields. Firstly, transition rates present a sensitive tool to investigate details of atomic structure since they probe static properties (atomic wave functions) as well as dynamic properties (electron correlation and relaxation). Secondly, an accurate knowledge of relative decay rates is important in practical applications In experimental studies of ion-atom collisions either fluorescence or electron emission is detected and the ionization cross sections are derived. In the L-shell case uncertainties of fluorescence and Coster-Kronig yields are a limiting factor upon deriving ionization cross sections. ... 

Comprehensive theoretical calculations of radiative transition rates as well as Auger and Coster-Kronig transition rates are available. However, uncertainties are large for Coster-Kronig transitions with small excess energy due to the strong influence of several effects (i) many-body interactions in the initial and final atomic systems, (ii) relaxation in the final ionic state, and (iii) exchange interaction between the continuum electron and the final bound-state electrons. For an experimental determination of decay rates, various techniques have been employed, e.g., the use of radioactive sources or coincidence techniques. Most techniques... 

In contrast to 3d and 4d levels 4p and 4s core levels have received less attention up to now either from EELS or from other core level spectroscopies. The case of 4p excitation is complicated by breakdown of the one-electron approximation for 4p core holes, which in this part of the Periodic Table may decay by 4p <—>4d f giant Coster-Kronig coupling, leading to broad ill-defined peaks in photoemission (Wendin 1981). In the rare earths (except Yb) such processes are allowed for 4pi/2 holes but not for 4p3/2- In electron loss the unstable 4p /2 excitations lead to ill-defined structure in the corresponding energy region, but sharp peaks are observed near the 4p3/2 ionisation threshold (Strasser et al. 1984). 

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