Theory of Optical Band Shape for A1g —T1u Transition. II

1975 ◽  
Vol 30 (8) ◽  
pp. 1060-1070
Author(s):  
Keiichiro Nasu
Keyword(s):  
Correlation Function ◽  
Characteristic Function ◽  
Phonon Dispersion ◽  
Peak Shift ◽  
Dyson Equation ◽  
Phonon Modes ◽  
Band Shape ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
The One

Abstract A theory of the optical band shape for A1g - T1u transitions is developed based on the method of the characteristic function. It covers the region of weak coupling between the electrons and the phonon modes of a1g , eg and t2g symmetries, and takes account of the phonon dispersion. It is bound that the cumulant function of the characteristic function can be described by a two-time phonon correlation function which includes the multi-phonon correlation due to the Jahn-Teller effect. A Dyson equation of the phonon correlation function is solved under specific conditions where the contribution from the eg modes is neglected and the phonons have a Lorentzian dispersion. Analytical expressions are given for intensity, peak shift and broadening of a few lower phonon side bands, and it is found that the one phonon side band of the t2g mode shifts to higher frequencies than that of the a1g mode.

scholarly journals Renormalization Group Approach to a One-Dimensional Cooperative T–e Jahn-Teller System

1977 ◽  
Vol 32 (1) ◽  
pp. 111-112
Author(s):  
S. Brühl ◽  
E. Sigmund
Keyword(s):  
Free Energy ◽  
Renormalization Group ◽  
Ising Model ◽  
Linear Chain ◽  
Group Approach ◽  
One Dimensional ◽  
Renormalization Group Approach ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
The One

Abstract A linear chain of T-e molecules exhibiting the cooperative Jahn-Teller effect is considered. Following Nauenberg's1 treatment of the one-dimensional Ising model a renormalization group approach is used. The series-expansion of the free energy is put into a closed form.

Experimental Determination of the key Energy Scales in the Colossal Magnetoresistive Manganites

1997 ◽  
Vol 494 ◽  
Author(s):  
D. S. Dessau ◽  
T. Saitoh ◽  
C.-H. Park ◽  
Z.-X. Shen ◽  
Y. Moritomo ◽  
...  
Keyword(s):  
Lattice Relaxation ◽  
Energy Scale ◽  
Layered Compounds ◽  
Ferromagnetic Phase ◽  
Colossal Magnetoresistive ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Atomic Exchange ◽  
Scale Mismatch ◽  
The One

ABSTRACTWe have performed X-ray absorption (XAS) and angle-resolved photoemission (ARPES) on single crystals of both the layered and cubic colossal magnetoresistive manganites to determine the electronic structure and the relevant energy scales in the problem: the intra-atomic exchange energy J (∼ 2.7 eV), the Jahn-Teller energy gain EJ-T (<.25 eV), the one-electron bandwidth W (>3 eV for layered compounds) and the lattice relaxation or polaron binding energy EB (.65 eV ferromagnetic phase and.8 eV paramagnetic phase). Lattice polarons are deemed important especially in the paramagnetic but also to a degree in the ferromagnetic phase. Due to the energy scale mismatch, the Jahn-Teller effect is unlikely to be the cause for these lattice polarons, at least for the layered samples.

Luminescence Properties of Thin-Film SrS:Cu Phosphors for Electroluminescent Displays

1998 ◽  
Vol 508 ◽  
Author(s):  
T.C. Jones ◽  
W. Park ◽  
E. Mohammed ◽  
B.K. Wagner ◽  
C.J. Summers ◽  
...  
Keyword(s):  
Thin Film ◽  
Fine Structure ◽  
Peak Shift ◽  
Peak Position ◽  
Teller Effect ◽  
Field Analysis ◽  
Excitation Wavelength ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Rigorous Treatment

AbstractThe origin of the electronic fine structure in thin-film SrS:Cu has been interpreted in terms of the several possible perturbations including spin-obit coupling, the Jahn-Teller effect and low symmetry splittings. Photoluminescence excitation measurements showed that the peak position of the excitation bands were independent of temperature suggesting that the electronic fine structure in our system was not due to the Jahn-Teller effect. Selective excitation measurements revealed that no peak shift occurs with changing excitation wavelength, indicating that Cu+ pairs or aggregates and Cu+-defect coupled centers were not existent in our system. Finally, several models were proposed for off-center displacements of Cu in SrS, since a rigorous treatment of these displacements is difficult. Both the tetragonal and trigonal distortion models for a <111> displacement yielded reasonable distortions parameters of 0. 16Å and 0.11Å, respectively. However, crystal field analysis showed that a <110> displacement was more likely since the energy level splitting scheme more closely resembled the observed data.

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.

EPR of Cu2+-doped Cs2CO3and CsHCO3: evidence of the Jahn–Teller effect

2009 ◽  
Vol 164 (2) ◽  
pp. 132-137
Author(s):  
Fevzi Köksal ◽  
Dilek Demir ◽  
Rahmi Köseoğlu
Keyword(s):  
Teller Effect ◽  
Jahn Teller ◽  
Jahn Teller Effect
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