Electron Paramagnetic Resonance facility (EPR)

Electron paramagnetic resonance (EPR) spectroscopy is also known as electron spin resonance (ESR) spectroscopy. It is the name given to the process of resonant absorption of microwave radiation by paramagnetic ions or molecules, with at least one unpaired electron spin, in the presence of a static magnetic field. EPR has a wide range of applications in chemistry, physics, biology and medicine. It may be used to probe the static structure of solid and liquid systems, and is also useful in investigating dynamic processes.

EPR spectroscopy provides an experimental route to study the magnetic interactions in paramagnetic materials. The elucidation of parameters like the electronic Zeeman interaction (g), hyperfine (A), nuclear quadrupole (Q) and zero-field or electronic quadrupole (D) tensors, which characterise the interactions, can lead to an understanding of atomic and molecular structure at magnetic sites. High sensitivity and the ability to investigate small scale order in powders, polymers, and frozen solutions are key advantages of EPR spectroscopy. Additional techniques employing both the EPR and NMR method (ENDOR-electronic nuclear double resonance) are available and extend the scope of such investigations. EPR spectroscopy can be combined with chemical techniques such as spin trapping to detect and follow free radical reactions in biological systems, etc.


Bruker Elexsys 500 Spectrometer

The EPR facility was originally comprised of a Bruker ESP 300 and a Bruker EMX spectrometer.

The ESP 300 has been decommissioned and replaced with a Bruker Elexsys 500 spectrometer through generous funding from the Wellcome Trust Equipment Fund.

Publications that arise from the use of this instrument should acknowledge the ARC and the Wellcome Trust Equipment Fund.

The Elexsys 500 has a 15” magnet equipped with rapid scan coils and can be operated in X-band (8-10 GHz), Q-band (35 GHz) or L-band (1.1) GHz modes.

A Super Hi-Q cavity is currently installed for use in X-band and has been used to examine metal complexes in pharmaceutical preparations, radical reactions, polymerisation processes and thin film deposits on plastics.

EMX Spectrometer

The EMX spectrometer has an 8” magnet and operates in the X-band mode.

This instrument is used for room temperature measurements of solids and special flat cells can be used for solution work.

The EMX has been used to examine metal complexes in the solid and in solution, polymerisation processes as well as coals and clays

How to use the facility

The facility is administered by Professor Peter Lay.

New users should discuss their proposed projects, time allocation and cost with Professor Peter Lay who will also provide training if necessary.

Use of the facility by University of Sydney scientists and students will incur charges of $30 per hour, long term projects can involve a yearly negotiable fee.

For other non-university users: The charge is $100 per hour, depending on the experiment required and the degree of involvement of the university. (under review)

All users will be asked to pay for any special supplies required for their experiments, i.e. tubes, cells and other consumables.


Peter Lay

ARC Professorial Fellow and Professor of Inorganic Chemistry
School of Chemistry
The University of Sydney NSW 2006 Australia
Room 307
T +61 2 9351 4269
F +61 2 9351 3329