Low Frequency EPR and EMR Point Spectroscopy and Imaging of a Surface

Area of Science:

• Spectroscopy
• Imaging Science
• Materials Science

Background:

• Low frequency electron paramagnetic resonance (LFEPR) spectrometers typically use large magnets for large samples.
• Conventional LFEPR methods are not optimized for imaging small, flat objects.

Purpose of the Study:

• To adapt LFEPR spectroscopy for imaging spatial distribution of spin probes on flat surfaces.
• To demonstrate the feasibility of LFEPR imaging for printed materials.

Main Methods:

• Utilized a 2.9 mm diameter surface coil with an LFEPR spectrometer (100-500 MHz).
• Recorded point spectra and scanned the sample under a fixed surface coil and magnetic field.
• Imaged the spatial distribution of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) spin probe and toner in printed letters.

Main Results:

• Successfully imaged the spatial distribution of DPPH and toner in printed letters.
• Demonstrated point spectral acquisition and spatial mapping capabilities of the adapted LFEPR technique.

Conclusions:

• LFEPR spectroscopy with a surface coil can image spin probe and material distribution on flat surfaces.
• This technique shows potential for non-destructive analysis of flat cultural heritage items like paintings and manuscripts.