Multifrequency EPR/ESR

Multifrequency EPR is the tool to disentangle magnetic field dependent from independent terms. Bruker BioSpin's EPR product range currently encompass two orders of magnitude in microwave frequencies:

• L- and S-Band: 1 GHz and 3.5 GHz
• X-Band: most common frequency at ca. 9.8 GHz
• K- and Q-Band : 24 GHz and 34 GHz
• W-Band: at 94 GHz

Soon, another factor of three up will be available with our 263 GHz project.

While the advantages of high frequency EPR are obivous, low frequency EPR is the perfect choice for large samples and in particular in-vivo studies (ELEXSYS E540).

Multifrequency EPR spectra renders simulation (e.g., with our XSophe or MolSophe) much more effective. Also, motion effects can be studied over a wide temporal range.

The majority of CW-EPR systems operates at X-Band. Thus, the first step into multifrequency CW-EPR is another operation frequency. In case of regular CW-EPR spectroscopy, Q-Band at 34 GHz is the best choice, because...

• Q-Band provides a threefold higher Zeemann energy
• Sample Size is still comparably large with 3 mm o.d.
• Q-Band probes with optional window or ENDOR capabilities are available

The following table provides a list of the most common EPR frequencies with their frequency range and g=2 field value for radical species, respectively (cf. also What is EPR? CW EPR Theory). All these frequencies are commonly offered by our selection of magnet systems.