Low temperature absorption spectra of KMnO4 in KClo4

Holt, Smith L.; Ballhausen, C. J.

doi:10.1007/bf00537508

Cited by 141 publications

(85 citation statements)

References 8 publications

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“…1 This supports the assignment of the experimental bands to the excitations with the electronic structure, as given in the DFT-SAOP excitation energy calculations; see the previous section.…”

Section: Vibronically Coupled Spectrasupporting

confidence: 85%

“…In this panel, we also give the model PESs that were obtained by diagonalization of the V(q) matrix for these 1 T 2 states using the Taylor expansion with linear and quadratic coupling constants (∂V ab /∂q 1 ) 0 and (∂ 2 V ab / ∂q 1 2 ) 0 , with q 1 being the a 1 mode for all of the intrastate and interstate matrix elements. The curves are obtained by calculating the V matrix from the Taylor expansion and diagonalizing it in a dense set of q 1 values, keeping all other q i equal to zero.…”

Section: Assessment Of the Model Potential Curvesmentioning

confidence: 99%

“…A well-resolved experimental spectrum was published in 1967 by Holt and Ballhausen. 1 Four band systems can be seen in this spectrum: (i) a very strong band with an origin at ca. 18 000 cm -1 with a very distinct strong vibrational progression of 770 cm -1 , (ii) a somewhat weaker band between 25 000 and 30 000 cm -1 , starting with two low-intensity peaks at ca.…”

Section: Introductionmentioning

confidence: 98%

“…In this d 0 system, the LUMO and LUMO + 1 are the d orbitals, 2e and 7t 2 exhibiting the ligand field splitting through antibonding mixing with the oxygen 2p, and the highest occupied levels are the 12 fully occupied oxygen 2p lone pair orbitals. The highest of these are the HOMO 1t 1 , which is 100% 2p by symmetry, and the HOMO -1 6t 2 , which has very little d admixture. Below these nonbonding levels are the 6a 1 , which is somewhat stabilized by admixture of the 4s, and the 1e and 5t 2 levels, which represent 2p orbitals that are more strongly stabilized by admixture with the 3d.…”

Section: Introductionmentioning

confidence: 99%

“…The highest of these are the HOMO 1t 1 , which is 100% 2p by symmetry, and the HOMO -1 6t 2 , which has very little d admixture. Below these nonbonding levels are the 6a 1 , which is somewhat stabilized by admixture of the 4s, and the 1e and 5t 2 levels, which represent 2p orbitals that are more strongly stabilized by admixture with the 3d.…”

Section: Introductionmentioning

confidence: 99%

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Vibronic Structure of the Permanganate Absorption Spectrum from Time-Dependent Density Functional Calculations

2005

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The UV absorption spectrum of the permanganate anion is a prototype transition-metal complex spectrum. Despite this being a simple d 0 T d system, for which a beautiful spectrum with detailed vibrational structure has been available since 1967, the assignment of the second and third bands is still very controversial. The issue can be resolved only by an elucidation of the intricate vibronic structure of the spectrum. We investigate the vibronic coupling by means of linear-response time-dependent density functional calculations. By means of a diabatizing scheme that employs the transition densities obtained in the TDDFT calculations in many geometries around R e , we construct a Taylor series expansion in the normal coordinates of a diabatic potential energy matrix, coupling 24 excited states. The simulated vibronic structure is in good agreement with the experimental absorption spectrum after the adjustment of some of the calculated vertical excitation energies. The peculiar blurred vibronic structure of the second band, which is a very distinctive feature of the experimental spectrum, is fully reproduced in the calculations. It is caused by the double-well shape of the adiabatic energy surface along the Jahn-Teller active e mode of the allowed 1 E state arising from the second 1 T 2 state, which exhibits a Jahn-Teller splitting into 1 B 2 and 1 E states. We trace the double-well shape to an avoided crossing between two diabatic states with different orbital-excitation character. The crossing can be explained at the molecular orbital level from the Jahn-Teller splitting of the set of 7t 2 {3d xy , 3d xz , 3d yz } orbitals (the LUMO + 1), to which the excitations characterizing the diabatic states take place. In contrast to its character in the two well regions, at R e the 2 1 T 2 state is not predominantly an excitation to the LUMO + 1, but has more HOMO -1 f LUMO (2e ) {3d x 2 -y 2 , 3d z 2 }) character. The changing character of the 2 1 T 2 -1 E state along the e mode implies that the assignment of the experimental bands to single orbital transitions is too simplistic intrinsically. This spectrum, and notably the blurring of the vibronic structure in the second band, can be understood only from the extensive configurational mixing and vibronic coupling between the excited states. This solves the long-standing assignment problem of these bands.

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Section: Vibronically Coupled Spectrasupporting

confidence: 85%

Section: Assessment Of the Model Potential Curvesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Vibronic Structure of the Permanganate Absorption Spectrum from Time-Dependent Density Functional Calculations

2005

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A density functional study of the electronic spectrum of permanganate

Dickson

Ziegler

1996

Int. J. Quantum Chem.

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Multiplet splittings for six excited electronic configurations of the permanganate ion, MnO;, are calculated. Earlier density functional calculations on the same subject are improved upon by the numerical evaluation of some two-electron integrals to resolve certain multideterminantal states. Excellent agreement with the experimental spectrum is obtained, and a reassignment of bands in the 25,000-35,000 cm-' range is proposed. Fully symmetric (a,) vibrational frequencies are calculated, and the origm and magnitude of the most significant Jahn-Teller distortions of the excited states are discussed. @ 1996

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