Electron paramagnetic resonance (EPR), also known as electron spin resonance (ESR), is a technique used to study the magnetic properties of materials containing unpaired electrons.
Here is a brief explanation of how electron paramagnetic resonance works:
Unpaired electrons: Many materials, such as transition metal ions or organic radicals, possess unpaired electrons. These unpaired electrons have intrinsic magnetic properties.
External magnetic field: A strong, static magnetic field is applied to the sample being studied. This field aligns the magnetic moments of the unpaired electrons in the sample.
Resonance condition: A microwave source emits electromagnetic radiation with a specific frequency, typically in the microwave range. The frequency is adjusted until it matches the resonance condition, where the energy of the microwave radiation corresponds to the energy difference between electron spin states.
Absorption of energy: When the resonance condition is met, the unpaired electrons can absorb energy from the microwave radiation and transition from one spin state to another. This absorption of energy is detected as a decrease in the intensity of the microwave radiation passing through the sample.
EPR spectrum: By varying the magnetic field strength, the absorption of energy is recorded as a function of the magnetic field. The resulting EPR spectrum shows distinct absorption peaks or lines, providing information about the magnetic properties of the sample, such as the number of unpaired electrons, their spin orientation, and their interaction with the surrounding environment.
Overall, EPR measures the response of unpaired electrons to external static magnetic fields and microwave radiation, allowing scientists to study the electronic structure and magnetic properties of materials. Therefore, EPR technology has a prominent role in many fields such as chemistry, biology, medicine, food and beverage, etc. CIQTEK's self-developed EPR spectrometer supports researchers in many application areas. Click to view the EPR application notes.
