Jahn-Teller induced corrections to rotational and fine-structure parameters in doubly degenerate electronic states

In order to determine the structure parameters of the reaction intermediate formed during the reduction process of chromate(VI) ion by hydrogen peroxide, a laboratory stopped-flow X-ray absorption fine structure (XAFS ) apparatus, which was constructed by a rotating anode X-ray generator, an energy scanning spectrometer, a stopped-flow assembly, and X-ray detectors, was newly developed. Using the apparatus, the Cr K -edge XAFS spectrum of the reaction intermediate was measured. One oxo group, two peroxo groups, and one water molecule are coordinated to the Cr(VI) center in the intermediate, CrO(O2)2(H2O ) , with Cr - O bond lengths of 157, 168, and 193 pm, respectively. The geometry around the Cr(VI) center is probably 6-coordinate pentagonal pyramidal.

Download Full-text

Spectral Fine Structure, Local Structure and Jahn-Teller Effect of α-Al2O3Crystal Doped with Ni2+

ACTA PHOTONICA SINICA ◽

10.3788/gzxb20103912.2183 ◽

2010 ◽

Vol 39 (12) ◽

pp. 2183-2189

Author(s):

殷春浩 YIN Chun-hao ◽

焦杨 JIAO Yang ◽

神干 SHEN Gan ◽

李富强 LI Fu-qiang ◽

朱姗姗 ZHU Shan-shan

Keyword(s):

Fine Structure ◽

Local Structure ◽

Teller Effect ◽

Jahn Teller ◽

Jahn Teller Effect

Download Full-text

Cooperative Pseudo Jahn-Teller Effect as Microscopic Mechanism of (OMT)-(LTT) Structural Phase Transition in La2−xBaxCuO4Superconductors

MRS Proceedings ◽

10.1557/proc-291-223 ◽

1992 ◽

Vol 291 ◽

Cited By ~ 1

Author(s):

Michael D. Kaplan

Keyword(s):

Phase Transition ◽

Structural Phase Transition ◽

Structural Phase ◽

Electronic States ◽

Teller Effect ◽

Excited Electronic States ◽

Microscopic Mechanism ◽

Jahn Teller ◽

Jahn Teller Effect ◽

Local Distortions

ABSTRACTA microscopic mechanism for the structural phase transition from the orthorhombic mediate temperature (OMT) phase into the low temperature tetragonal (LTT) one is suggested on the basis of the cooperative pseudo Jahn-Teller effect. The local distortions mixing the ground and the first excited electronic states are ordered antiferrodistortively and are connected in part, with the oxygen octahedra rotations around the [100] axis. The results are in agreement, with the neutron scattering experiments data.

Download Full-text

Calculation of the fine-structure parameters for np 5 n′f configurations of rare-gas atoms

Optics and Spectroscopy ◽

10.1134/1.1335026 ◽

2000 ◽

Vol 89 (6) ◽

pp. 811-816 ◽

Cited By ~ 2

Author(s):

G. P. Anisimova ◽

E. L. Kapel’kina ◽

R. I. Semenov

Keyword(s):

Fine Structure ◽

Rare Gas ◽

Structure Parameters ◽

Rare Gas Atoms

Download Full-text

Correlation of Zero Field Splittings and Site Distortions V. Mn2+ in Cs2Zn3S4

Zeitschrift für Naturforschung A ◽

10.1515/zna-1983-0209 ◽

1983 ◽

Vol 38 (2) ◽

pp. 149-153 ◽

Cited By ~ 2

Author(s):

M. Heming ◽

G. Lehmann

Keyword(s):

Fine Structure ◽

Hyperfine Splitting ◽

Site Symmetry ◽

Zero Field ◽

Structure Parameters ◽

Zero Field Splitting ◽

Zero Field Splitting Parameter ◽

Free Ion ◽

Splitting Parameter ◽

Epr Signal

Abstract In platelets of Cs2Zn3S4 with about 4% of the Zn substituted by Mn two nonequivalent centers of isolated Mn2+ were observed in addition to a broad EPR signal near g = 2 which is assigned to clusters of interconnected MnS4 units. The fine structure and hyperfine structure parameters for the single-ion centers (all in units of 1CT 4 cm -1) areb02 = -318.3 ± 3; b22 = -210.3 ± 2; Ay = -62.7; Az = -63.6 ± 0.8;b02 = -890 ± 18; b22 = -743 ± 36; Ay = -60.6; Az = - 61.4 ± 0.8;for centers I and II, resp. Center II arises from Zn sites of C 2 site symmetry while for center I assignment to either one of two sites with D2 site symmetry is possible. The larger hyperfine splitting constants as well as the superposition analysis favor the larger sites which are not occupied by Zn, but are partly occupied in the analogous Mn (and Co) compounds. Superposition analysis yields the same value of + 0.12 ± 0.02 cm-1 for the intrinsic zero field splitting parameter b̄2 of the bridging MnS4 units in both sites. gz is significantly higher than the free ion value indicating a higher degree of covalency than in Cds and CdGa2S4.

Download Full-text