The jahn—teller effect and vibronic interactions in modern chemistry

Берсукер, И. Б.; Blake, Antony B.

doi:10.1016/s0003-2670(00)85373-8

Cited by 160 publications

(153 citation statements)

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“…The other motion in an octahedral complex is the triply degenerate F 1u mode. It will be shown in what follows that these two vibronic modes lead to both a lowering of the energy in the degenerate excited 1 T 1u electronic state and a reduction of the cubooctahedral symmetry from which the absorption transitions originate, these two properties being the key characteristics 20 of the Jahn-Teller effect.…”

Section: M/rgmentioning

confidence: 94%

Simulation of atomic zinc luminescence in rare gas solids: A localized pair potentials approach

McCaffrey¹,

Kerins²

1997

The Journal of Chemical Physics

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The luminescence spectroscopy of atomic zinc isolated in the solid rare gases ͑Zn/RG͒ is compared with theoretical predictions obtained from the sum of diatomic Zn•RG and RG•RG pair potentials. In particular the existence of pairs of emission bands, both of which are assigned to the same gas phase electronic transition, is examined with the use of diatomic pair potentials to simulate the potential energy surfaces of the Jahn-Teller active vibrational modes of Zn in the solid rare gases Ar, Kr, and Xe. Simulations of the solid state Zn/RG luminescence are developed from a consideration of the excited state Zn( 1 P 1 )•RG n van der Waals cluster species in the gas phase. The maximum binding energy of the Zn( 1 P 1 )•RG n clusters is found in the Zn•RG 4 cluster having a square planar structure at the energy minimum. Based on the results of the cluster calculations, lattice distortions which led to a dominant interaction between the Zn atom and four of its host atoms were sought to simulate the solid state luminescence. Two such vibronic modes were identified; one a lattice mode in which four rare gas atoms contract on a single plane toward the Zn atom, referred to as the waist mode, and the other a motion of the Zn atom toward an octahedral interstitial site of the lattice, the body mode. Energy calculations of these modes were carried out for rigid and relaxed rare gas lattices allowing identification of the high energy emission bands in the Zn/RG systems as arising from the waist mode, while the lower energy bands are associated with the body mode. The model also rationalizes the differences exhibited in the time-resolved behavior of the pairs of singlet emission bands in the Zn/Ar and Zn/Kr systems, whereby the lower energy band of a given system shows a risetime of a few hundred picoseconds while the higher energy band exhibits direct feeding. The steep gradient calculated on the waist mode, feeding the high energy band, and the flat gradient found on the body mode, feeding the lower energy emission, are consistent with the existence of a risetime in the latter and its absence in the former. The close agreement found between theory and experiment indicates the validity of using pair potentials in analysis of matrix zinc spectroscopy and thereby indicates that the luminescence is controlled by localized guest-host interactions.

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Section: M/rgmentioning

confidence: 94%

Simulation of atomic zinc luminescence in rare gas solids: A localized pair potentials approach

McCaffrey¹,

Kerins²

1997

The Journal of Chemical Physics

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“…24 These equations predict sizable Jahn-Teller coupling within the 2 E g state. The ground state b 2g bending vibration is 190 cm −1 , and the predicted coupling 2e is some 12 times this vibrational energy, so the L z S z spin-orbit matrix element within the 2 E g state would be expected to be completely quenched.…”

Section: Ligand Field Spectramentioning

confidence: 99%

The highly resolved electronic spectrum of the square planar CuCl42− ion

Dick

Rahemi

Krausz

et al. 2008

The Journal of Chemical Physics

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Articles you may be interested inAbsence of exchange interaction between localized magnetic moments and conduction-electrons in diluted Er3+ gold-nanoparticles J. Appl. Phys. 115, 17E128 (2014) The low temperature magnetic circular dichroism ͑MCD͒ and electron paramagnetic resonance ͑EPR͒ spectra of Cu͑II͒ doped Cs 2 ZrCl 6 are reported. The Cu͑II͒ ion is incorporated as the square planar copper tetrachloride ion, CuCl 4 2− , which substitutes at the Zr͑IV͒ site in the Cs 2 ZrCl 6 lattice, with a complete absence of axial coordination. Both the EPR and MCD show highly resolved spectra from which it is possible to determine the superhyperfine coupling constants and excited state geometries respectively. The Franck-Condon intensity patterns suggest that there is a substantial relaxation of the host lattice about the impurity ion. For the lowest energy 2 B 1g ͑x 2 -y 2 ͒ → 2 B 2g ͑xy͒ transition, both the magnetic dipole allowed electronic origin as well as vibronic false origins are observed. The high resolution of the spectra allowed the accurate determination of the odd parity vibrations that are active in the spectra. The opposite sign of the MCD of the two components of the 2 E g ͑xz , yz͒ excited state allows this splitting to be determined for the first time. Accurate and unambiguous spectral parameters for the CuCl 4 2− ion are important as it has become a benchmark transition metal complex for theoretical electronic structure calculations.

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“…For this comparison, we chose the mode depicted in Figure 3 from the set of two degenerate modes. It corresponds to the Q θ (X 1 -X 2 -X 3 + X 4 ) symmetrized displacement according to ref 38 and leads to a D 2d symmetric structure, in which two of the three former degenerate 1 T 2 states fall into irreducible representation E and remain degenerate (solid curves), whereas the third one is of B 2 symmetry (dotted curves). The model curves follow the calculated points perfectly close to the equilibrium geometry, so the second-order Taylor expansion is adequate.…”

Section: Assessment Of the Model Potential Curvesmentioning

confidence: 99%

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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The jahn—teller effect and vibronic interactions in modern chemistry

Cited by 160 publications

References 0 publications

Simulation of atomic zinc luminescence in rare gas solids: A localized pair potentials approach

Simulation of atomic zinc luminescence in rare gas solids: A localized pair potentials approach

The highly resolved electronic spectrum of the square planar CuCl42− ion

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

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