Jahn-Teller distortions theory

It was shown by several workers that in this case the first-order Jahn-Teller distortion is due to an e 2 vibration, and that the second-order distortion vanishes. Therefore, in terms of simple Jahn-Teller theory, the moat around the symmetric point should be a Mexican hat type, without secondary minima. This expectation was borne out by high-level quantum chemical calculations, which showed that the energy difference between the two expected Civ structures (2A2 and 2B ) were indeed very small [73],... 

J-acid, 9 402, 403 Jackets, heat-transfer, 16 111—718 Jacobsen s ligand, 20 305 Jacobson-Stockmayer theory, in siloxane polymer manufacture, 22 558 Jacquinot advantage, 14 228 J-aggregation, 9 508 Jahn-Teller distortion, 22 203 Jahn—Teller effect, 6 611 Jai Tire process, 21 476 Jameson cell, 16 653 Jamming phase diagram, 12 18 Jams... 

Jahn-Teller distortion, 41 266-267 potential energy diagram, 41 278 structural chemistry, 41 264 VSEPR theory, 41 265-266 heats of formation of gaseous atoms of, 14 123... 

The absorption spectrum of the bare Cu Y zeolite was also measured and interpreted using a model of a CuII-0(Sl ) site. The 0-CuII-0 angle was determined to be 117° from optical spectra, in excellent agreement with 115.9° found by X-ray crystallography (20). Based upon the observed spectral splitting of 1800 cm- of the states of Cu -, first order vibronic theory predicted a Jahn-Teller distortion of 0.05-0.06 A along the Cu11- bonds. 

Polynuclear clusters fill the gap between mononuclear and extended solid transition metal vibronic systems. The applications of the theory of vibronic interaction allow to describe physical and chemical properties of these systems, sometimes directly linked to their application. The Jahn-Teller distortion found for the rhenium clusters defines the architecture of hybrid inorganic-organic materials and, as a result, their electric and magnetic properties. The application of the vibronic theory to the decatungstate cluster elucidates the details of its reactivity in the photocatalytic reaction. The modern DFT methods give a key to the calculations of key parameters of the vibronic theory. In future, we will assist at the combination of these methods with phenomenological approaches leading to the description of vibronic effects in physical and chemical properties of polynuclear clusters from first principles. 

Recently, approximate MO theories have been applied to a wide range of solid-state phenomena in addition to those reviewed in this paper. A short review of some of these problems indicates its versatility. Messmer and Watkins (3) have used EH to predict the position of N impurity levels in diamond using a 35-atom C lattice. Their calculations indicated the presence of a Jahn-Teller effect in accordance with electron paramagnetic resonance (EPR) experiments. The calculation was successful in explaining the deepening of the N donor level as due to Jahn-Teller distortion. 

The temperature dependence of A-site Jahn-Teller distortions has also been discussed by Kanamori (322). The phase transition in this case is of the first kind. Comparison of theory and experiment for CuCr204 is shown in Figure 54. 

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