EPR spectroscopy uses microwaves and a magnetic field to measure the energy levels of unpaired electrons in paramagnetic materials. The document discusses EPR theory, describing how electron spin states diverge in a magnetic field. It also details the specific EPR spectrometer used in the author's lab, including its 9.5GHz microwave frequency. Finally, it explains how EPR can test battery materials like those used in the lithium-ion batteries developed for Mars rovers.

1. EPR
(electron paramagnetic resonance)
By Jonathan Spagnola

2. EPR Theory
• Electrons have two spin energy
states
• When no magnetic-field, the
energy of the spin states are
identical
• In presence of magnetic field,
the energy of spin states diverge
• EPR is only used on
paramagnetic species

3. EPR spectroscopy
 The instrument used in the
lab is Bruker EMX model
spectrometer.
 The frequency of the
microwaves that the
spectrometer produce is
9.5GHz.
 EPR spectrum of LiMn2O4

4. EPR Practicality
• The spectrometer can also be used to
test the efficiency of different
combinations of atoms, such as Li-
ion batteries.
• The batteries for the mars rover were
developed by those in the lab I
currently work in.
• So, why Lithium?
• Lithium ion batteries are one of the
most common rechargeable sources
of energy.