Photoelectron Spectroscopy AKA Photoemission Spectroscopy Types of PES

Photoelectron Spectroscopy AKA Photoemission Spectroscopy

Types of PES X-ray Photoelectron Spectroscopy (XPS) - using soft x-rays (with a photon energy of 200 -2000 e. V) to examine core-levels. Ultraviolet Photoelectron Spectroscopy (UPS) - using vacuum UV radiation (with a photon energy of 1045 e. V) to examine valence levels.

X-ray Photoelectron Spectroscopy

PES - Chlorine Photo Electron Spectra Relative Number of Electrons Chlorine 1000 10 Energy 1 0, 1 Energy is scaled in MJ/mol. 1 megajoule = 1000 k. J Credit to Thomas Silak for the PES Excel Spreadsheet

PES - Chlorine Photo Electron Spectra Relative Number of Electrons 2 p 1 s 1000 3 p 3 s 2 s 100 Chlorine 10 Energy 1 0, 1 1 s electrons require the most energy for removal due to their proximity to the nucleus. Credit to Thomas Silak for the PES Excel Spreadsheet

PES - Chlorine Photo Electron Spectra Relative Number of Electrons 2 p Chlorine 3 p 1 s 1000 3 s 2 s 100 10 Energy 1 0, 1 3 p peak essentially represents the first ionization energy, as an outermost electron is being removed. Credit to Thomas Silak for the PES Excel Spreadsheet

Carbon and Nitrogen Relative Number of Electrons Photo Electron Spectra 2 p 2 s 2 s 2 p 1 s 1 s 100 Carbon Nitrogen 10 Energy 1 0, 1 Removal of electrons from nitrogen requires more energy, due to a greater nuclear charge. Credit to Thomas Silak for the PES Excel Spreadsheet

Oxygen and Nitrogen Relative Number of Electrons Photo Electron Spectra 2 p Oxygen Nitrogen 2 p 1 s 1 s 100 2 s 2 s 10 1 0, 1 Energy 2 p electron is easier to remove in oxygen due to electron repulsion is paired 2 p orbital. Credit to Thomas Silak for the PES Excel Spreadsheet

Sodium and Potassium Photo Electron Spectra Relative Number of Electrons 2 p 1 s 1000 1 s 100 2 s 2 p 3 p Sodium Potassium 2 s 3 s 10 Energy 3 s 4 s 1 0, 1 Electrons are harder to remove from potassium, due to the greater nuclear charge. The first ionization energy is smaller, because the electron is farther from the nucleus, and more shielded. Credit to Thomas Silak for the PES Excel Spreadsheet