EPRspektroskopialla

EPR spectroscopy, also known as Electron Paramagnetic Resonance spectroscopy or Electron Spin Resonance spectroscopy, is a spectroscopic technique used to detect and measure the presence of unpaired electrons in a sample. Unpaired electrons are those that reside in atomic or molecular orbitals by themselves, rather than being paired with another electron. The presence of unpaired electrons makes a substance paramagnetic, meaning it is attracted to a magnetic field.

The principle behind EPR spectroscopy relies on the magnetic properties of unpaired electrons. When a sample containing unpaired electrons is placed in a strong external magnetic field, the spins of these electrons align either with or against the field, creating two distinct energy levels. By applying microwave radiation of a specific frequency, energy can be absorbed by the unpaired electrons as they transition from the lower energy level to the higher energy level. This absorption occurs at a particular magnetic field strength, which is characteristic of the type of unpaired electron and its surrounding chemical environment.

The EPR spectrum is a plot of microwave absorption versus magnetic field strength. The position and shape of the absorption signal provide valuable information about the electronic structure, oxidation state, and molecular environment of the species containing unpaired electrons. EPR spectroscopy finds applications in a wide range of fields, including chemistry, physics, biology, and materials science. It is used to study free radicals, transition metal ions, defects in solids, and the mechanisms of chemical reactions.