ORBITAL ORDERING IN LaMnO3: CLUSTER MODEL CALCULATION OF RESONANT X-RAY SCATTERING AND X-RAY ABSORPTION AT THE MnL2,3 EDGE

2002 ◽  
Vol 09 (02) ◽  
pp. 1167-1171 ◽  
Author(s):  
M. TAGUCHI ◽  
M. ALTARELLLI
Keyword(s):  
Linear Dichroism ◽  
Orbital Ordering ◽  
Teller Distortion ◽  
X Ray ◽  
X Ray Scattering ◽  
Jahn Teller ◽  
Crystal Field Parameters ◽  
X Ray Absorption ◽  
Jahn Teller Distortion ◽  
Ray Scattering

We report theoretical results for resonant X-ray scattering (RXS) and linear dichroism (LD) in X-ray absorption spectra at the Mn L 2,3 edge in LaMnO 3, with special attention to the observation of orbital ordering. Calculations were performed on a ( MnO 6)10- cluster with D 4h symmetry, including the effect of intra-atomic multiplet coupling in the Mn ion. Anisotropy effects are also included, through the anisotropic Mn 3d– O 2p hybridization and crystal field parameters for Mn 3d states. The agreement between theory and experiment is good. Moreover, we show that the intensity of the peaks at the L 3 edge are strongly dependent on the Jahn–Teller distortion, while the peaks at the L 2 edge are mostly related to the orbital ordering.

5d STATES AND RESONANT X-RAY SCATTERING FROM CeB6

2002 ◽  
Vol 09 (02) ◽  
pp. 1203-1207
Author(s):  
TATSUYA NAGAO ◽  
JUN-ICHI IGARASHI
Keyword(s):  
Dominant Role ◽  
Earth Metal ◽  
Metal Compound ◽  
Teller Distortion ◽  
X Ray ◽  
X Ray Scattering ◽  
Jahn Teller ◽  
Jahn Teller Distortion ◽  
Good Agreement ◽  
Ray Scattering

We study the origin of the resonant X-ray scattering (RXS) signal near the Ce L III absorption edge in the antiferroquadrupolar (AFQ) ordering phase of CeB 6. In this rare-earth metal compound, the intra-atomic Coulomb interaction plays a dominant role to give the large RXS intensities, which shows a sharp contrast with the Jahn–Teller distortion mechanism realized in the transition metal compound such as LaMnO 3. The temperature and magnetic field dependences show good agreement with the recent experiment, indicating that the RXS signal is a direct reflection of the AFQ order parameter.

RESONANT X-RAY SCATTERING IN YTiO3 AND YVO3

2002 ◽  
Vol 09 (02) ◽  
pp. 1197-1201
Author(s):  
MANABU TAKAHASHI ◽  
JUN-ICHI IGARASHI
Keyword(s):  
Local Density ◽  
Band Structure Calculation ◽  
Orbital Ordering ◽  
Teller Distortion ◽  
X Ray ◽  
X Ray Scattering ◽  
Cast Doubt ◽  
Jahn Teller ◽  
The Difference ◽  
Ray Scattering

We investigate the Ti and V K edge resonant X-ray scattering spectra in YTiO 3 and YVO 3 by using ab initio band structure calculation based on the local density approximation. The calculated spectra show good agreement with recent experiments, although the effect of the orbital ordering is neglected, while that of the lattice distortion is taken into account in the calculation. Particularly, the observed drastic change of the spectra for the (100) reflection between the low temperature and intermediate temperature phases of YVO 3 is nicely explained by the difference of the Jahn–Teller distortion between the two phases. These results cast doubt on an assertion that the resonant X-ray scattering is a direct observation of the orbital order in YTiO 3 and YVO 3.

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>

scholarly journals Stability of Jahn-Teller distortion inLaMnO3under pressure: An x-ray absorption study

2007 ◽  
Vol 75 (5) ◽  
Author(s):  
Aline Y. Ramos ◽  
Hélio C. N. Tolentino ◽  
Narcizo M. Souza-Neto ◽  
Jean-Paul Itié ◽  
Liliana Morales ◽  
...  
Keyword(s):  
Absorption Study ◽  
Teller Distortion ◽  
X Ray ◽  
Jahn Teller ◽  
X Ray Absorption ◽  
Jahn Teller Distortion

Temperature-dependent X-ray absorption near edge spectroscopy of doped LaMnO3: Ion-size and the Jahn–Teller distortion effects

2009 ◽  
Vol 404 (8-11) ◽  
pp. 1404-1408 ◽  
Author(s):  
Y.T. Tsai ◽  
W.J. Chang ◽  
S.W. Huang ◽  
J.-Y. Lin ◽  
J.Y. Lee ◽  
...  
Keyword(s):  
Temperature Dependent ◽  
Teller Distortion ◽  
X Ray ◽  
Jahn Teller ◽  
Ion Size ◽  
X Ray Absorption ◽  
Jahn Teller Distortion

CHARGE AND ORBITAL ORDER IN THE ELECTRON DOPED MAGNANITE (Bi,Ca)MnO3

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1661-1666 ◽  
Author(s):  
P. D. HATTON ◽  
S. B. WILKINS ◽  
P. D. SPENCER ◽  
D. MANNIX ◽  
S. D. BROWN ◽  
...  
Keyword(s):  
Transition Metal Oxides ◽  
High Energy ◽  
Charge Ordering ◽  
Orbital Ordering ◽  
Orbital Order ◽  
X Ray ◽  
X Ray Scattering ◽  
Jahn Teller ◽  
Structural Modulation ◽  
Ray Scattering

The interplay between charge, spin and orbital degrees of freedom in transition metal oxides has been a matter of much interest in recent years. In this paper we present X-ray scattering results of charge and orbital ordering in the electron doped manganite Bi 0.24 Ca 0.76 MnO 3. Using High Energy X-ray Scattering (HEXS) the charge ordering, structural modulation due to the Jahn–Teller ordering and the harmonic of the structural modulation have been measured. The superlattice reflections due to the Jahn–Teller ordering are found to maximise in intensity at the Neél point. We have confirmed using resonant X-ray scattering at the K-edge of manganese and the Anisotropic Tensor of Susceptibility technique (ATS) that superlattice reflections occurring at a modulation wavevector of (0.5, 0, 0) are due to charge ordering in a Mn 3+/ Mn 4+ ordering pattern. In addition superlattice reflections corresponding to the orbital order were measured at a modulation wavevector of (0.25, 0, 0). The temperature dependence of both the Jahn–Teller structural distortion peak (1.75, 2, 0) and the charge ordering peak (3 0 0) were observed to behave identically, gradually increasing with decreasing temperature.

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