Related Experiment Video
Updated: Mar 14, 2026

Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
Evidence of spin-temperature in dynamic nuclear polarization: an exact computation of the EPR spectrum
Filippo Caracciolo1, Marta Filibian1, Pietro Carretta1
1University of Pavia, Department of Physics, Via Bassi 6, 27100-Pavia, Italy. filippo.caracciolo01@universitadipavia.it.
Abstract:
In dynamic nuclear polarization (DNP) experiments, the compound is driven out-of-equilibrium by the microwave (MW) irradiation of the radical electron spins. Their stationary state has been recently probed via electron double resonance (ELDOR) techniques showing, at low temperature, a broad depolarization of the electron paramagnetic resonance (EPR) spectrum under microwave irradiation. In this theoretical manuscript, we develop a numerical method to compute exactly the EPR spectrum in the presence of dipolar interactions. Our results reproduce the observed broad depolarisation and provide a microscopic justification for the spectral diffusion mechanism. We show the validity of the spin-temperature approach for typical radical concentration used in dissolution DNP protocols. In particular once the interactions are properly taken into account, the spin-temperature is consistent with the non-monotonic behavior of the EPR spectrum with a wide minimum around the irradiated frequency.
More Related Videos
Related Concept Videos
Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
Nuclear Overhauser Enhancement (NOE)
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
Atomic Nuclei: Nuclear Spin State Population Distribution

