The ESRg matrix for strong field d5 systems

Abstract

This review has tried to collect and correlate all the various equations for the g matrix of strong field d5 systems obtained from different basis sets using full electron and hole formalism calculations. It has corrected mistakes found in the literature and shown how the failure to properly take in symmetry boundary conditions has produced a variety of apparently inconsistent equations in the literature. The review has reexamined the problem of spin-orbit interaction with excited t4e states and finds that the earlier reports that it is zero in octahedral symmetry is not correct. It has shown how redefining what x, y, and z are in the principal coordinate system simplifies, compared to previous methods, the analysis of experimental g values with the equations

A perspective on applications of ligand-field analysis: inspiration from electron paramagnetic resonance spectroscopy of coordination complexes of transition metal ions

“…This is not so. As recently discussed by Slep and coworkers, 63 the best approach for analyzing magnetic or EPR data even for such an S = 1/2 system is by a complete ligand-field analysis using the entire d 5 64,65 The many pitfalls of extracting electronic configuration from the observed g values, such as their assignment to g x , g y , g z , are clearly explained in these papers. We will reproduce one such set of equations from one of McGarvey's papers, namely for tetragonally distorted LS d 5 , with the real d orbital basis set.…”

“…This indicates that the complex is significantly distorted from octahedral geometry, which might be the result both of crystal packing effects involving the cations (particularly relevant for a highly charged complex such as hexacyanoferrate/cobaltate) and Jahn- , where L is a variety of imino ligands), the directions of the g matrix components can be very different from what might be expected based on the molecular structure, as a consequence of π-bonding and other complicated effects. 62,64,65 We next turn to transition metal systems that have more than one unpaired electron and are in HS ground states, in contrast to the LS d 7 and d 5 cases mentioned above. The first of these is "HS" d 8 (the quotation marks because the "LS" form is not really appropriate for octahedral symmetry, but for square planar).…”

Preparation and Characterization of a Microcrystalline Non‐Heme FeIII(OOH) Complex Powder: EPR Reinvestigation of FeIII(OOH) Complexes—Improvement of the Perturbation Equations for the g Tensor of Low‐Spin FeIII

“…These expressions lead to signed values for g. However, only the absolute g values are determined in most experiments and will be dealt with in the rest of the paper (for discussions on the sign of the g values see, for example, references [11][12][13]). The absolute g values are represented in Figure 6 case is frequently encountered in LS heme systems, [11] whereas the negative value of D' case occurs in non-heme Fe III A C H T U N G T R E N N U N G (OOH) model complexes.…”

“…[11][12][13] Herein, we report the isolation of LS [Fe III 6 ) 2 , which is the first example of a microcrystalline powder for such a thermally unstable intermediate. The temperature-dependent magnetic susceptibility and the EPR properties of this complex were studied and are reported herein.…”

“…*: g min values calculated from Equation (6);~: g min values calculated from Equation (7), in which e 0 1 and e 0 2 were obtained from Equations (4) and (5); and^: g min value calculated from Equation (13), in which D' was obtained from a diagonalization calculation.…”