Abstract AbstractElectron paramagnetic resonance (EPR) spectroscopy can be used to analyze paramagnetic substances, that is, substances with unpaired electrons. Electrons have two different energy configurations or levels when placed in an external magnetic field. The electronic energy levels vary in energy depending on the substance the electron is in. Researchers can record a spectrum for each substance by sending fixed frequency photons into the substance and sweeping the magnetic field.
Conventional EPR spectrometers operate at 9 GHz and tend to be destructive to the sample. On the other hand, an EPR spectrometer operating at a lower frequency (0.441 GHz) can be nondestructive, but very little work has been done on these instruments. Therefore, we have created a library/database of low frequency EPR spectra for common pigments used in paintings. Pigments, even ones with similar optical properties that are hard to distinguish from each other by traditional methods, possess unique EPR spectra that can be used to identify them. The database also includes information about the history of each pigment, therefore, it can be of use to museum curators and art collectors and historians to determine the authenticity and the age of a painting.