Non-Kramers systems

For Kramers (e.g. one-electron) states where the eigenvalue of T2, A = — 1, the metric gAA is antisymmetric, and so relating to symplectic algebras (in relativistic terms to pure torsion rather than to curvature), rather than symmetric as for non-Kramers systems. The joint action of Hermitian conjugation and time reversal (which is not commutative) is summarized with the above results for these individual operations in Table 1. 

Surerus, K. K. Hendrich, M. P. Christie, P. D. Rottgardt, D. Orme-Johnson, W. H. Miinck, E. Mossbauer and integer-spin EPR of the oxidized P-clusters of nitrogenase POX is a non-Kramers system with a nearly degenerate ground doublet. J. Am. Chem. Soc. 1992, 114(22), 8579-8590. 

These studies provide the first advanced EPR studies of a non-Kramers doublet spin system, and they suggest the possibility of investigating similar signals from other proteins in this family. EXAFS spectroscopy does not exhibit Fe- -Fe backscattering in Hred (38). This observation could reflect thermal motion, or it may suggest that, as a consequence of the reduction of Hox to Hred, the Fe-Fe distance has... 

FIGURE 5.13 Effective -values for integer spin systems in axial symmetry. The scheme gives the g-values for all transitions within the non-Kramer s doublets of S = n systems assuming greal = 2.00 and 5 5 5 B cubic zero-field terms are ignored. 

Hagen, W.R. 1982b. EPR of non-Kramers doublets in biological systems characterization of an S = 2 system in oxidized cytochrome c oxidase. Biochimica et Biophysica Acta 707 82-98. 

If I understand the column correctly, a 1-factor model was used. Well, a single linear factor can never be sufficient to properly model a non-linear system. A minimum of 2 factors are required. (Richard Kramer)... 

FIGURE 1.12 VTVH MCD for a non-Kramers 5 = 2 system with rhombic distortion. Panel (a) plots the data as a function of f)H/2kT and panel (b) as a function of HkT. The inset shows the effect of ZFS and a magnetic field on the Ms = 2 ground-state wavefunction.30... 

As shown in Figure 1.12a, a non-Kramers S = 2 system with rhombic distortion will show significant nesting in its saturation magnetization curves. 

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