Auger Process and Notation

The Auger process involves three steps:
1) A core electron is removed by the photoelectric process
2) An electron from a higher orbital falls down almost immediately to fill this hole (a radiationless transition)
3) Excess energy of the exited state ion is removed by the ejection of an Auger electron.

A schematic of this process for a KL2L3 transition is shown in Figure 1. Nomeclature used for the description of Auger transtions are presented in Table 1. Refer to the reference provided for a more in-depth description. Figure 1. Schematic showing the three steps involved in the Auger process. The KL2L3 Auger transition is illustrated. The open circles symbolize holes (absence of electrons) [1].

Table 1. X-ray notation of electron energy states [1].
The higher transitions are N1 = 4s2, N2,3 = 4p6, N4,5 = 4d10, O1 = 5s2 etc., P1 = 6s2 etc. Q1 = 7s2 etc.
[1] Richard P. Gunawardane and Christopher R. Arumainayagam in "Handbook of Applied Solid State Spectroscopy" Chapter 10, Auger Electron Spectroscopy, Springer, pp 451 - 483 (2006).