Photoelectron Spectroscopy (PES) A data source that confirms the shell/subshell model of the atom High-energy light (X-rays or short wave UV) ejects electrons from the atom By measuring kinetic energy of the particles, we can derive the existence of different sublevels in the atom
Image Source: SPECS GmbH, Photoelectron Spectroscopy
3+ X-ray or UV Source X-ray or UV Source Kinetic Energy Analyzer Binding Energy (MJ/mol)
Kinetic Energy Analyzer Negative Voltage Hemisphere Slightly Less Negative Voltage Hemisphere
Negative Voltage Hemisphere Positive Voltage Hemisphere If Kinetic energy is too high… Negative Voltage Hemisphere Slightly Less Negative Voltage Hemisphere
Negative Voltage Hemisphere Positive Voltage Hemisphere If voltage is too high… Negative Voltage Hemisphere Slightly Less Negative Voltage Hemisphere
X-ray or UV Source X-ray or UV Source Binding Energy (MJ/mol) Boron Li Kinetic Energy Analyzer
Photoelectron Spectroscopy (PES) A self-paced PES online professional development webinar is available for free on AP Central. wf/ap-webcasts/chemistry/ap_chem_pes.html wf/ap-webcasts/chemistry/ap_chem_pes.html
Shells and Subshells Activity In small groups, work through the activity sheets together If your group finishes early, see if you can write an assessment question (or two) involving PES data spectra can be found on the Arizona site or in the Dropbox