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 molecules.
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 levels with different values of magnetic spin quantum number (MS=0,±1) are separated and the Zeeman splitting dictates their separation. In the absence of magnetic field, the 3 levels of the triplet are isoenergetic to the first order. However, when we incorporate the effect one electron has on the other, the energy of the sublevels of the triplet are separated out (zero field splitting). The separation of these sub levels manifest in peaks of the frozen solution EPR spectrum.
Famous quotes containing the words field and/or splitting:
“... many American Jews have a morbid tendency to exaggerate their handicaps and difficulties. ... There is no doubt that the Jew ... has to be twice as good as the average non- Jew to succeed in many a field of endeavor. But to dwell upon these injustices to the point of self-pity is to weaken the personality unnecessarily. Every human being has handicaps of one sort or another. The brave individual accepts them and by accepting conquers them.”
—Agnes E. Meyer (1887–1970)
“I had an old axe which nobody claimed, with which by spells in winter days, on the sunny side of the house, I played about the stumps which I had got out of my bean-field. As my driver prophesied when I was plowing, they warmed me twice,—once while I was splitting them, and again when they were on the fire, so that no fuel could give out more heat. As for the axe,... if it was dull, it was at least hung true.”
—Henry David Thoreau (1817–1862)