Electronic spectrum of hydroxopentaamminechromium(III)

Decurtins, Silvio; Guedel, Hans U.; Neuenschwander, K.

doi:10.1021/ic50170a014

Cited by 18 publications

(10 citation statements)

References 37 publications

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“…This problem has been addressed by Güdel [10] and by Flint [11], who have reported results from calculations which have included spin-orbit coupling. There is a considerable advantage, however, in having an actual set of wavefunctions and matrix 0340-4811 / 81 / 1200-1276 $ 01.00/0.…”

Section: Introductionmentioning

confidence: 99%

Spin-Orbit Coupling in Tetragonal d³ Systems

Hoggard

1981

Zeitschrift Für Naturforschung A

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The complete set of energy matrices for tetragonal d 3 systems, including spin-orbit coupling, has been constructed within the framework of the Angular Overlap Model. Examples are presented of the variation in energy of the intraconfigurational (t\t) doublets as a function of spinorbit coupling (appropriate to first row metal ions) and ligand field asymmetry. It is seen that asymmetry in Dq values is much less important than the relative partitioning of Dq into ea and en • The use of spin-orbit matrix elements in the calculation of intensities of spin-forbidden transitions is also illustrated.

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Section: Introductionmentioning

confidence: 99%

Spin-Orbit Coupling in Tetragonal d³ Systems

Hoggard

1981

Zeitschrift Für Naturforschung A

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“…This is strong evidence for dissimilar nuclear geometries in the two states [12,15] [12] exemplify this type of emission. In glassy matrices, the vibronic bands are unresolved, resulting in broad and featureless spectra, which show large solvent dependence [26,28].…”

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confidence: 72%

“…The energies of the 2E components are largely insensitive to quadrate fields, while the 2EQ component of 2TI is stabilized through configuration interaction with the higher energy 2EQ component of 2T2 [10,11]. In complexes with large enough quadrate fields, 2EQ can fall below the components of the cubic 2E state [10,11,12] hence becoming the emitting state [12,13,14,15]. For brevity the ground state and the quadrate components of the cubic 2E state will be referred to by their octahedral symmetry labels, while the spin-orbit components of the quadrate 2E state will be referred to as 2EQ.…”

Section: State Ordering In Quadrate Fieldsmentioning

confidence: 99%

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Emission of pyridine and polypyridine chromium(III) complexes in rigid and fluid media

Ghaith¹

1988

J. Phys. Chem.

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by the Cl atom through occupation of the d22 orbital, while in passing from the quartet to sextet, the additional charge loss is absorbed by the four porphyrin nitrogen atoms via covalent mixing with the dxx.yy orbital.In passing from the doublets through the quartets to the sextets there is also a systematic increase in 4S population. This increase seems to be reflected in the observed Mossbauer isomer shifts <5 that increases roughly from about 0.17 ± 0.07 mm/s for the doublets to about 0.40 ± 10 mm/s for the sextet. ConclusionsIn this study we examine the ground and excited states properties of (porphinato)iron(III) chloride as a model for ferric porphyrin complexes. For the geometry and chelation we assume, 6Alg and 1234A2g states are predicted to lie very near in energy. As suggested by many others, and as discussed in the text, two states so close in energy could both be thermally populated or they might mix directly through spin-orbit coupling to form Kramers doublets in which only Jz is a good quantum number. The nature of these two states, and indeed their mixing, will be a sensitive function of the details of the model assumed.Four spin states of 2Eg and 2B2g symmetry are predicted to lie lowest under stronger ligand fields. For our model structure the 2Eg state is predicted about 1800 cm'1 lower in energy than the 2B2g. The calculated Mossbauer quadrupole splitting for the 2Eg state of 1.91 mm/s is in reasonable agreement with the range of values observed for low spin complexes, 1.7-2.3 mm/s. The electronic spectra of (porphinato)iron(III) chloride is calculated assuming ground-state symmetries 6Alg, 4A2g, 2Eg, and 2B2g. The low-lying excitations are in good agreement with experimental values when they are known. The Q band in the visible is well reproduced. Porphyrin triplet states are predicted to gain intensity through spin coupling through the central metal, and we suggest their role in the spectra observed below the Q band. The 6Alg has considerable mixing between eg(rr) and metal dT (dX2 and d>2) orbitals leading to a predicted intensity pattern among the many allowed Eu excited states that is quite sensitive to details of geometry and calculation. In our calculation, as well as in the ab initio calculations of Rawlings, et al.26 a "split Soret" is predicted for the 6Alg. The B or Soret band is predicted some 6000 cm'1 higher in energy than observed.No reliable spectra for a spin 3/2 complex is available but we are not certain these calculations could be used to distinguish the 4A2g and 6Alg spectra. Both suggest low-lying bands about 10400 cm'1, weakly allowed bands at about 15 000 cm'1, a Q band about 16 500 cm"1 and even one component of a split Soret at about 24000 cm"1 (see Tables VI and VII). The calculated spectra from the 2Eg state are in reasonable agreement with that observed and again suggest the 2Eg state is the lowest doublet.Acknowledgment. This work was supported in part through grants from the CRDEC Chemical Systems Technology Research Center at the University of Florida, DAAA15-8...

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“…Following Griffith [3], I proposed that this was due to a failure of the spherical parameterization of the electron-electron interaction due to metal-ligand overlap [22]. This was described by Gűdel as very worrying [23], but seems to be a general phenomenon [24,25]. The effect appears similar to the failure of the simple crystal field model in lanthanide complexes and has been attributed to electron correlation induced by the crystal field (CCF).…”

Section: Energy Transfermentioning

confidence: 99%