Four electron (or hole) noncubic ligand field spectrum. I. Tetragonal energy levels

1974 ◽  
Vol 78 (26) ◽  
pp. 2678-2682 ◽  
Author(s):  
Jayarama R. Perumareddi
Keyword(s):  
Energy Levels ◽  
Ligand Field ◽  
Field Spectrum

Ligand Field-Spin Orbit Energy Levels in the d4 and d6 Electron Configurations of Octahedral and Tetrahedral Symmetry

1974 ◽  
Vol 29 (1) ◽  
pp. 31-41 ◽  
Author(s):  
E. König ◽  
S. Kremer
Keyword(s):  
Strong Field ◽  
Energy Levels ◽  
Coulomb Repulsion ◽  
Orbit Interaction ◽  
Complete Agreement ◽  
Ligand Field ◽  
Spin Orbit ◽  
Tetrahedral Symmetry ◽  
Spin Orbit Interaction ◽  
Orbit Perturbation

The complete ligand field -Coulomb repulsion -spin orbit interaction matrices have been derived for the d4 and d6 electron configurations within octahedral (Oh) and tetrahedral (Td) symmetry. The calculations were perform ed in both the weak-field and strong-field coupling schemes and complete agreement of the results was achieved. The energy matrices are parametrically dependent on ligand field (Dq), Coulomb repulsion (B, C) and spin-orbit interaction (ζ). Correct energy diagrams are presentend which display the splittings by spin-orbit perturbation as well as the effect of configuration mixing. Applications to the interpretation of optical spectral data, to the detailed behavior at the crossover of ground terms, and to complete studies in magnetism are pointed out.

scholarly journals Ligand-Field Spin-Orbit Energy Levels in the d5 Electron Configuration of Octahedral and Tetrahedral Symmetry

1974 ◽  
Vol 29 (3) ◽  
pp. 419-428 ◽  
Author(s):  
E. König ◽  
R. Schnakig ◽  
S. Kremer
Keyword(s):  
Strong Field ◽  
Energy Levels ◽  
Orbit Interaction ◽  
Complete Agreement ◽  
Ligand Field ◽  
Electron Configuration ◽  
Spin Orbit ◽  
Tetrahedral Symmetry ◽  
Spin Orbit Interaction ◽  
Orbit Perturbation

The complete ligand-field, Coulomb interelectronic repulsion, and spin-orbit interaction matrices have been derived for the d5 electron configuration within octahedral (Oh) and tetrahedral (Td) symmetry. The calculations were performed in both the weak-field and strong-field coupling schemes and complete agreement of the results was achieved. The energy matrices are parametrically dependent on ligand field (Dq), Coulomb repulsion (B, C), and spin-orbit interaction (ζ). Correct energy diagrams are presented which display the splittings by spin-orbit perturbation as well as the effect of configuration mixing. Applications to the interpretation of electronic spectra, and to complete studies in magnetism are pointed out. The detailed behavior at the crossover of ground terms is considered

The ligand field spectrum of K3[Cr(OH)6]

1988 ◽  
Vol 150 (1-2) ◽  
pp. 127-128 ◽  
Author(s):  
A. Ceulemans ◽  
B. Coninckx ◽  
C. Görller-Walrand ◽  
H. Jacobs ◽  
J. Bock
Keyword(s):  
Ligand Field ◽  
Field Spectrum

Synthesis and ligand field spectrum of potassium heptafluoroniobate(IV)

1974 ◽  
Vol 13 (9) ◽  
pp. 2242-2245 ◽  
Author(s):  
L. O. Gilpatrick ◽  
L. M. Toth
Keyword(s):  
Ligand Field ◽  
Field Spectrum

Theoretical analysis of the ligand field spectrum of K3CoF6

1994 ◽  
Vol 224 (1-2) ◽  
pp. 207-212 ◽  
Author(s):  
L.G. Vanquickenborne ◽  
K. Pierloot ◽  
E. Duyvejonck
Keyword(s):  
Theoretical Analysis ◽  
Ligand Field ◽  
Field Spectrum

ChemInform Abstract: LIGAND FIELD SPECTRUM AND THE ELECTRONIC STRUCTURE OF THE HEXACYANOCHROMATE(3-) ION

1984 ◽  
Vol 15 (38) ◽  
Author(s):  
L. G. VANQUICKENBORNE ◽  
L. HASPESLAGH ◽  
M. HENDRICKX ◽  
J. VERHULST
Keyword(s):  
Electronic Structure ◽  
Ligand Field ◽  
Field Spectrum

Ligand Field-Actuated Non-Innocence of Acetylacetonate

2020 ◽  
Author(s):  
Morten Gotthold Vinum ◽  
Laura Voigt ◽  
Steen Hansen ◽  
Colby Bell ◽  
Kensha Marie Clark ◽  
...  
Keyword(s):  
Noble Metals ◽  
Chemical Reactivity ◽  
Energy Levels ◽  
Orbital Energy ◽  
Ligand Field ◽  
Ligand Orbital ◽  
Catalytic Cycles ◽  
Electrochemical Potentials ◽  
New Strategies ◽  
Metal Ligand

<p>The quest for simple ligands to participate in concerted base metal-ligand multiple-electron redox events is driven by perspectives of replacing noble metals in catalysis and for discovering novel chemical reactivity. Yet the vast majority of simple ligand systems displays electrochemical potentials impractical for catalytic cycles substantiating the importance of new strategies towards aligned metal–ligand orbital energy levels. We herein demonstrate the possibility to establish and tame the elusive <i>non-innocence</i> of the ubiquitous acetylacetonate (acac), that is the most commonly employed anionic, chelating ligand towards elements across the entire Periodic Table. By employing the ligand field in the high-spin Cr(II) as a thermodynamic switch, we were able to chemically tailor the occurrence of metal–ligand redox events. The very mechanism can be understood as a destabilization of the d<i><sub>z</sub></i>2 orbital relative to the <i>pi</i>* LUMO of acac, which proffers a generalizable strategy to synthetically engineer non-innocence with seemingly redox-inactive ligands. </p>

Ligand field spectrum and the electronic structure of the hexacyanochromate(3-) ion

1984 ◽  
Vol 23 (12) ◽  
pp. 1677-1684 ◽  
Author(s):  
L. G. Vanquickenborne ◽  
L. Haspeslagh ◽  
M. Hendrickx ◽  
J. Verhulst
Keyword(s):  
Electronic Structure ◽  
Ligand Field ◽  
Field Spectrum

The angular overlap model applied to chiral chromophores and the parentage interrelation of absolute configurations

1967 ◽  
Vol 297 (1448) ◽  
pp. 96-133 ◽  
Keyword(s):  
Radial Function ◽  
Energy Levels ◽  
Basis Functions ◽  
Basis Set ◽  
Ligand Field ◽  
Matrix Elements ◽  
Function Model ◽  
First Order ◽  
Angular Overlap Model ◽  
Overlap Model

The interpretation of the circular dichroism (c. d.) of coordination compounds is discussed with particular reference to the ligand field transitions of d 3 and low-spin d 6 systems. The experimental crystal spectra indicate by their large intensities that the solution spectra have to be interpreted on the basis of large cancellations caused by the overlapping of positive and negative c. d. contributions from closely lying energy levels. Some quantitative consequences of this have been derived. Symmetry considerations and the angular overlap model have been applied to tris(bidentate) and cis -bis(bidentate) chromophores which in most cases have been considered ortho-axial except for the perturbation due to the chelation. This perturbation and the chirality caused by the chelation have been described in terms of the small angular parameters ( δ and ϵ ) which represent a displacement of the ligating atoms, the ligators, away from the ortho-axial positions. The molecular orbital orientation of the angular overlap model has been demonstrated, and the ligand field perturbation within this model has been given as a sum of a σ and two different π contributions, corresponding to ligator π orbitals vertical and parallel to the plane of the chelating ligands. For the σ part of the perturbation, which is considered the most important part, the matrix elements connecting orbitals within each cubic subset ( e and t 2 ), for some matrix elements in contrast with the results of the electrostatic model, do not depend on δ and ϵ to first order. However, e and t 2 orbitals are connected by σ terms, first order in δ and ϵ . The perturbation energies can also be separated in a different way, also in order of decreasing importance, the regularly octahedral perturbation, the non-octahedral orthoaxial perturba­tion and finally the perturbation due to chelation. It is recommended to treat d n systems by considering first and together the effect of the octahedral part of the perturbation and that caused by the interelectronic repulsion, and diagonalize with respect to these two perturba­tions before the smaller perturbation contributions are considered. This can be done within the expanded radial function model, which considers the interelectronic repulsion parametrizable as in spherical symmetry. With the purpose of illuminating this the field strength series of ligands, ordering the ligands according to their values of ∑ = ∆/ B Racah , has been given. ∑ is the parameter of the expanded radial function model which determines the extent of the mixing of pure cubic subconfigurations. The symmetry restrictions imposed upon ligand field operators in order to make them able to contribute to rotational strengths are discussed on the basis of a rotational strength pseudo tensor. When this is expressed with respect to our standard basis functions it can be written as a symmetrical matrix with the same symmetry properties as the corresponding energy matrix except for sign changes by improper rotations. The parentage problem for inter­relating absolute configurations is discussed also on the basis of the tensor. A comparison between the results of the angular overlap model and those of the electro­static model is made. Throughout the usual real d -functions have served as our limited basis set, and these functions together with the real p -functions define the standard octahedral irreducible representations. Functions belonging to these standard octahedral bases are generally not symmetry adapted with respect to our whole gerade perturbation, but they are symmetry adapted to the main part of it, the (holohedrized) octahedral part. Re-diagonalization of the whole perturbation with respect to functions which are diagonal for the combined perturba­tions of the holohedrized octahedral ligand field and the interelectronic repulsion, has the advantage of moving by far most of the gerade lower symmetry perturbation into the diagonal. This means that the energy levels become described almost completely by linear combina­tions of our standard cubic basis functions which belong to the same irreducible representa­tion of the octahedral group, but which are symmetry adapted to the whole perturbation. These functions will, in general, be connected by small non-diagonal elements which mix the purely gerade-cubic levels. Since the polarization properties of the c. d. are governed by the directions of the magnetic dipole transition moments involved, they can be directly obtained for the linear combinations mentioned, on the basis of the very simple polarization properties of the standard cubic basis components.

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