Zero field splitting
Encyclopedia
Zero field splitting describes various interactions of the energy levels of an electron spin (S>1/2) even in the absence of an applied magnetic field. It is important in the electron spin resonance of biological molecule
s.
The value of the ZFS parameter is usually defined as D. Values of D have been obtained for a wide number of organic biradicals by EPR
/ESR measurements. This value may be measured by other magnetometry techniques such as SQUID
, however EPR measurements provide more accurate data in most cases.
For an S=1 spin system, in the presence of a magnetic field, the singlet and triplet are separated and the Zeeman splitting dictates their separation. To first order the 3 levels of the triplet are isoenergetic. However, when we incorporate the effect one electron has on the other, the energy of the sublevels of the triplet are separated out. The separation of these sub levels manifest in peaks of the frozen solution EPR spectrum.
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
s.
The value of the ZFS parameter is usually defined as D. Values of D have been obtained for a wide number of organic biradicals by EPR
Electron paramagnetic resonance
Electron paramagnetic resonance or electron spin resonance spectroscopyis a technique for studying chemical species that have one or more unpaired electrons, such as organic and inorganic free radicals or inorganic complexes possessing a transition metal ion...
/ESR measurements. This value may be measured by other magnetometry techniques such as SQUID
SQUID
A SQUID is a very sensitive magnetometer used to measure extremely weak magnetic fields, based on superconducting loops containing Josephson junctions....
, however EPR measurements provide more accurate data in most cases.
For an S=1 spin system, in the presence of a magnetic field, the singlet and triplet are separated and the Zeeman splitting dictates their separation. To first order the 3 levels of the triplet are isoenergetic. However, when we incorporate the effect one electron has on the other, the energy of the sublevels of the triplet are separated out. The separation of these sub levels manifest in peaks of the frozen solution EPR spectrum.