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
Photoelectron Spectroscopy
Image Source: SPECS GmbH, http://www.specs.de/cms/front_content.php?idart=267
Kinetic Energy Analyzer
X-ray or UV
Source
6.26
0.52
Binding Energy (MJ/mol)
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
3+
Kinetic Energy Analyzer
Negative Voltage
Hemisphere
1 Joule
1 Volt =
1 Coulomb
1 e− = 1.602 x 10−19 Coulombs
1 eV = 1.602 x 10−19 Joules
1 mole of eV = 96 485 J
10.364 eV = 1 MJ/mol
Slightly Less
Negative
Voltage
Hemisphere
If Kinetic energy is too high…
Negative Voltage
Hemisphere
Positive
SlightlyVoltage
Less
Hemisphere
Negative
Voltage
Hemisphere
If voltage is too high…
Negative Voltage
Hemisphere
Positive
SlightlyVoltage
Less
Hemisphere
Negative
Voltage
Hemisphere
Kinetic Energy Analyzer
X-ray or UV
Source
Li
6.26
0.52
Binding Energy (MJ/mol)
Boron
1.36 0.80
19.3
Binding Energy (MJ/mol)
5+
5+
3+
3+
5+
5+
3+
5+
3+
5+
5+
3+
3+
5+
3+
5+
3+
5+
5+
3+
5+
3+
3+
5+
3+
5+
5+
3+
3+
5+
5+
3+
5+
3+
5+
3+
Photoelectron Spectroscopy
(PES)
A
self-paced PES online professional
development webinar is available for free
on AP Central.

http://media.collegeboard.com/digitalServices/s
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