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How to Identify Auger Peaks in XPS Spectra - The Easy Way!
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How to Identify Auger Peaks in XPS Spectra - The Easy Way!

How to Identify OJ PS and XPS Spectrum

Understanding Peaks in XPS Spectrum

  • The video discusses how to recognize and identify OJ PS (Auger Peaks) and XPS (X-ray Photoelectron Spectroscopy) Spectrum, emphasizing that the number of peaks depends on three parameters: chemical environment, physical state of the sample, and instrumental contributions.
  • An example is given using lead as a heavy element, which shows a large number of photoelectron peaks. The OJ peaks are typically found at higher binding energy for most elements.
  • A key identification feature of OJ PS is that they appear less intense compared to other peaks. High-resolution spectra show these as broad humps rather than sharp peaks.

Overview of the OJ Process

  • The process begins with shining X-rays on core electrons, resulting in photoelectrons. When a vacancy is created in the core level, it can be filled by valence electrons, leading to the emission of an Auger electron.
  • This process can create two holes when one electron fills a vacancy while another escapes from the outer shell; this phenomenon is referred to as "double."

Series Observable in Auger Electrons

  • There are four main observable OJ series: KLL, LMM, MNN, and NNN. These series indicate which shells are involved in filling vacancies and emitting electrons.
  • For larger elements like lead, all four series can be observed. Each notation (e.g., KLL or LMM) describes where the initial vacancy was created and which electron filled it.

Kinetic Energy Considerations

  • The kinetic energy of an Auger electron correlates with the binding energies of core electrons involved in filling vacancies. It’s calculated based on differences between these binding energies.
  • Importantly, the binding energy of core electrons remains constant regardless of the type of X-ray source used (aluminum vs magnesium), highlighting its intrinsic property related to material characteristics.

Independence from X-ray Source

  • The kinetic energy of Auger electrons does not change with different X-ray sources; this independence emphasizes that variations in source do not affect measured values significantly.
  • However, while kinetic energies remain consistent across sources, calculated binding energies may vary depending on specific conditions or assumptions made during analysis.
Playlists: XPS - X-rays Photoelectron Spectroscopy
Video description

How to Identify Auger Peaks in XPS Spectra? Several types of peaks can be observed in XPS spectra. The chemical environment and other physical and chemical state of the sample can increase/decrease the peaks in XPS spectra. Also the instrumental contribution should be considered. 1- Photoelectron Peaks 2- Auger Peaks 3- X-rays Satellite Peaks 4- X-rays Ghost Peaks 5- Shake-Up Peaks 6- Shake- off peaks 7- Multiplet splitting 8- Energy Loss Lines 9- Valence Lines and Bands Let's discuss Auger Peaks The Auger peaks are usually appear at the higher Binding Energy (BE) of the XPS spectra and the peaks are usually broad like hump. These peaks are produced when the core electron vacancy filled by valence electrons and the subsequent emission of electron from the same level. There are four main Auger series observable in XPS namely KLL, LMM, MNN and NOO series, identified by specifying the initial and final vacancies in the Auger transition, where K, L, M, N, and O are shells. For instance, the KLL peak means that the initial vacancy occurs in the K-shell, the vacancy is filled by the L-shell electron and subsequent emission of electron from the L-shell. There are also similar notation like KVV, where V for valence level, which means that the final vacancies (double vacancies) are in the valence level. The Kinetic Energy (KE) of the Auger electron can be calculated by KEAuger ~ BE(K) - BE(L1) - BE(L3) The KE of the Auger electron depends on the BE of specific orbitals in the atom from which it is originated. The BE of these orbitals are independent of the types of x-rays sources used so the KE of the Auger electrons is also independent on the type of x-rays source used. Therefore, with different x-ray sources, the calculated BE of the Auger electrons will changed Please subscribe to my channel and share it. Thank you!