What improves the resolution in EPR spectroscopy?

High magnetic fields and pulsed EPR significantly improve the resolution in electron paramagnetic resonance (EPR) spectroscopy. High magnetic fields increase the separation between energy levels of the electron spins, enhancing the sensitivity of the technique and allowing for better differentiation between closely spaced spectral lines. This results in sharper peaks in the EPR spectrum, which is critical for accurate analysis of the electronic structure and dynamics of paramagnetic species.

Pulsed EPR techniques further complement the improvement in resolution by enabling the acquisition of time-domain data, which can be transformed into frequency-domain spectra. This time-resolved approach reduces the effects of inhomogeneous broadening that often occur at lower magnetic fields, ultimately leading to enhanced resolution and improved insights into the molecular environment of the paramagnetic centers being studied.

In contrast, low magnetic fields tend to produce broader resonances due to increased inhomogeneous broadening, while temperature control and sample size can have effects on signal intensity and noise but do not inherently improve the spectral resolution as directly as high magnetic fields and pulsed techniques do.