Local Jahn-Teller distortion inLa1−xSrxMnO3observed by pulsed neutron diffraction

1997 ◽  
Vol 56 (14) ◽  
pp. R8475-R8478 ◽  
Author(s):  
Despina Louca ◽  
T. Egami ◽  
E. L. Brosha ◽  
H. Röder ◽  
A. R. Bishop
Keyword(s):  
Neutron Diffraction ◽  
Teller Distortion ◽  
Jahn Teller ◽  
Pulsed Neutron ◽  
Jahn Teller Distortion

Neutronenbeugungsmessungen an Li2CrCl4 / Neutron Diffraction Studies of Li2CrCl4

1989 ◽  
Vol 44 (10) ◽  
pp. 1203-1205 ◽  
Author(s):  
Peter Kuske ◽  
Jeremy Karl Cockcroft ◽  
Heinz Dieter Lutz
Keyword(s):  
Neutron Diffraction ◽  
Elevated Temperatures ◽  
Inverse Spinel ◽  
Lithium Ions ◽  
Teller Distortion ◽  
Inverse Spinel Structure ◽  
Jahn Teller ◽  
Jahn Teller Distortion ◽  
High Temperature Polymorph ◽  
Large Disorder

Neutron diffraction studies of Li2CrCl4 at 350 °C are presented. The cubic high-temperature polymorph of Li2CrCl4 (space group Fd3̅m, Z = 8, R = 3.26%) crystallizes in an inverse spinel structure (cF56) with large Frenkel disorder of the tetrahedrally coordinated lithium ions. The occupation of the interstitial octahedral 16c sites by lithium ions is 38%, that of the tetrahedral 8a lattice sites only 24%. This large disorder is obviously the reason of the high ionic conductivity of Li2CrCl4 at elevated temperatures. There are some indications of a dynamic Jahn-Teller distortion of the CrCl6 units.

Enhancement of the guest orderliness in a low-symmetric perovskite-type metal–organic framework influenced by Jahn–Teller distortion

2018 ◽  
Vol 20 (34) ◽  
pp. 21809-21813 ◽  
Author(s):  
M. Viswanathan
Keyword(s):  
Neutron Diffraction ◽  
Single Crystal ◽  
Metal Organic Framework ◽  
Teller Distortion ◽  
Unusual Effect ◽  
Jahn Teller ◽  
Metal Organic ◽  
Jahn Teller Distortion ◽  
Perovskite Type ◽  
Organic Framework

Single-crystal neutron diffraction reveals an enhancement of the guest-orderliness in a low-symmetric MOF, with an opposite scenario for its high-symmetric cousin. The mechanism behind this unusual effect is proposed.

Evidence for a Jahn-Teller Distortion in the CMR Layered Manganite La1.4Sr1.6Mn2O7

1997 ◽  
Vol 494 ◽  
Author(s):  
Despina Louca ◽  
G. H. Kwei ◽  
J. F. Mitchell
Keyword(s):  
Function Analysis ◽  
Layered Compounds ◽  
Crystallographic Structure ◽  
Teller Distortion ◽  
Atomic Pair ◽  
Pair Density ◽  
Jahn Teller ◽  
Pulsed Neutron ◽  
Jahn Teller Distortion ◽  
Comparable Magnitude

ABSTRACTThe changes with temperature in the crystallographic structure of the two-layered La1.4Sr1.6Mn2O7, are on average quite small but the atomic pair density function analysis of pulsed neutron diffraction data shows that the lattice is locally distorted in accordance with the change in the transport properties. In particular, while no Jahn-Teller (JT) distortion is expected in the layered compounds because the octahedral bilayers are almost cubic, lattice distortions attributed to a large JT effect are present and are of comparable magnitude as in the cubic perovskite system. This could in turn explain the similarity in their properties. The number of the JT distorted sites is reduced with temperature concomitantly with the decrease in resistivity of the ab-plane.

scholarly journals Structure of copper tellurite and borotellurite glasses by neutron diffraction, Raman, 11B MAS-NMR and FTIR spectroscopy

2020 ◽  
Vol 61 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Amandeep Kaur ◽  
Atul Khanna ◽  
P. S. R. Krishna ◽  
A. B. Shinde ◽  
Marina González-Barriuso ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Tellurite Glass ◽  
Mas Nmr ◽  
Melt Quenching ◽  
Teller Distortion ◽  
X Ray ◽  
Glass Forming ◽  
Heat Treated ◽  
Jahn Teller ◽  
Jahn Teller Distortion

The structure of copper tellurite and borotellurite glasses is studied by x-ray and neutron diffraction, reverse Monte Carlo (RMC) simulations, FTIR, Raman and 11B MAS-NMR spectroscopy. Copper tellurite sample with 15 mol% CuO forms precipitates of tetragonal TeO2 within the glass matrix on melt quenching. The glass forming ability of the xCuO–(100−x)TeO2 system enhances with increase in CuO concentration from 15 to 20 mol% and also with the addition of B2O3. RMC simulations on the neutron diffraction data found that the Cu–O and Te–O bond lengths are approximately at equal distances in the range: 1·96 to 1·98±0·02 Å, while the nearest O–O distance is at 2·71±0·02 Å. Neutron and Raman results on the Te–O speciation are in agreement and confirmed that the Te–O coordination decreases with an increase in CuO and B2O3 molar concentrations in the tellurite and borotellurite glasses, respectively. RMC studies found that Cu2+ has tetrahedral coordination with oxygen, as predicted by Jahn–Teller distortion and that Cu–O and Te–O structural units have very similar size and geometry. The copper tellurite glass-ceramic sample with 15 mol% CuO was heat treated and it formed crystalline precipitates of TeO2 and CuTe2O5 upon devitrification; the average Te–O coordination was significantly smaller in the glass as compared to that in the crystalline sample.

The Interplay of Open-Shell Spin-Coupling and Jahn-Teller Distortion in Benzene Radical Cation Probed by X-ray Spectroscopy

2020 ◽  
Author(s):  
Marta L. Vidal ◽  
Michael Epshtein ◽  
Valeriu Scutelnic ◽  
Zheyue Yang ◽  
Tian Xue ◽  
...  
Keyword(s):  
High Harmonic ◽  
Open Shell ◽  
Spin Coupling ◽  
High Symmetry ◽  
Teller Distortion ◽  
Spectral Window ◽  
X Ray ◽  
Jahn Teller ◽  
X Ray Absorption ◽  
Jahn Teller Distortion

We report a theoretical investigation and elucidation of the x-ray absorption spectra of neutral benzene and of the benzene cation. The generation of the cation by multiphoton ultraviolet (UV) ionization as well as the measurement of<br>the carbon K-edge spectra of both species using a table-top high-harmonic generation (HHG) source are described in the companion experimental paper [M. Epshtein et al., J. Phys.<br>Chem. A., submitted. Available on ChemRxiv]. We show that the 1sC -> pi transition serves as a sensitive signature of the transient cation formation, as it occurs outside of the spectral window of the parent neutral species. Moreover, the presence<br>of the unpaired (spectator) electron in the pi-subshell of the cation and the high symmetry of the system result in significant differences relative to neutral benzene in the spectral features associated with the 1sC ->pi* transitions. High-level calculations using equation-of-motion coupled-cluster theory provide the interpretation of the experimental spectra and insight into the electronic structure of benzene and its cation.<br>The prominent split structure of the 1sC -> pi* band of the cation is attributed to the interplay between the coupling of the core -> pi* excitation with the unpaired electron<br>in the pi-subshell and the Jahn-Teller distortion. The calculations attribute most of<br>the splitting (~1-1.2 eV) to the spin coupling, which is visible already at the Franck-Condon structure, and estimate the additional splitting due to structural relaxation to<br>be around ~0.1-0.2 eV. These results suggest that x-ray absorption with increased resolution might be able to disentangle electronic and structural aspects of the Jahn-Teller<br>effect in benzene cation.<br>

Jahn-Teller Effect in Hexahydroxocuprate(II) Complexes

1995 ◽  
Vol 60 (9) ◽  
pp. 1429-1434
Author(s):  
Martin Breza
Keyword(s):  
Hydrogen Bonding ◽  
Quantum Chemical ◽  
Potential Surface ◽  
Hydroxyl Group ◽  
Chemical Calculation ◽  
Teller Distortion ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Extremal Values ◽  
Jahn Teller Distortion

Using semiempirical CNDO-UHF method the adiabatic potential surface of 2[Cu(OH)6]4- complexes is investigated. The values of vibration and vibronic constants for Eg - (a1g + eg) vibronic interaction attain extremal values for the optimal O-H distance. The Jahn-Teller distortion decreases with increasing O-H distance. The discrepancy between experimentally observed elongated bipyramid of [Cu(OH)6]4- in Ba2[Cu(OH)6] and the compressed one obtained by quantum-chemical calculation is explainable by hydrogen bonding of the axial hydroxyl group.

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