Department of Chemistry

Analytical Spectroscopy Laboratory

Bruker ESR Spectrometer

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The Bruker ESP300 Electron Spin Resonance spectrometer is a standard Continuous Wave X-Band instrument.

This instrument will record the electron paramagnetic resonance absorption spectra of samples which have unpaired electrons, (aka free radicals).  Samples may be liquids, solutions, or solids.  The standard variable temperature controller can control the temperature between ca.100K to ca. 200C.  An auxilliary liquid helium refrigerator can control the temperature down to ca. 4K.

The picture shows the sample in a 4 mm quartz sample tube inserted into the standard rectangular cavity.  The cavity is supported at the bottom of ca. 1 meter of X-band waveguide, located between the poles of an electromagnet.  This magnet can produce homogeneous magnetic fields between 100-10,000 Gauss (0.01 - 1 Tesla).

Above the top of the picture sits the microwave bridge. This produces and detects the microwaves which are transmitted to the cavity and reflected back from it.  The microwave frequency can be controlled from 9.1-9.9 GHz, and between nanowatts up to 200 milliwatts of power.   

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