A high-pressure Raman study of FeTiO3 ilmenite: Fermi resonance as a manifestation of Fe-Ti charge transfer

The high-pressure Raman spectra of the v1 and 2 v2 Fermi doublet of CO2 and the C-H stretching, C-H bending and C-C-C breathing modes of naphthalene have been studied at pressures varying up to 2000 bar and temperatures between 60 and 90°C. The naphthalene bands show a blue frequency shift with increasing density, whereas a red shift for the Fermi resonance free stretching mode of CO2 is observed with increasing density. The blue shift is explained in terms of repulsive interactions probed by the naphthalene vibrations, while the red shift is related to the attractive forces dominating in the intermolecular potential as seen by the CO2 stretching mode. The experimental results support the validity of the site-to-site model of intermolecular potential. The intermolecular potential between naphthalene and CO2 is assumed to be anisotropic, and the proposed electrostatic quadrupole-quadrupole model of these interactions effectively explains the anisotropy in the intermolecular potential, the energy of association, and the frequency shifts.

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ChemInform Abstract: HIGH PRESSURE RAMAN STUDY OF INTERMOLECULAR INTERACTIONS AND FERMI RESONANCE IN LIQUID ETHYLENE CARBONATE

Chemischer Informationsdienst ◽

10.1002/chin.198514049 ◽

1985 ◽

Vol 16 (14) ◽

Author(s):

W. SCHINDLER ◽

T. W. ZERDA ◽

J. JONAS

Keyword(s):

High Pressure ◽

Intermolecular Interactions ◽

Ethylene Carbonate ◽

Fermi Resonance ◽

Raman Study

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High-Pressure Raman Study of Liquid and Crystalline CH2F2up to 29 GPa

Journal of the Physical Society of Japan ◽

10.1143/jpsj.63.934 ◽

1994 ◽

Vol 63 (3) ◽

pp. 934-940 ◽

Cited By ~ 4

Author(s):

Wu Youhong ◽

Mitsukazu Onomichi ◽

Shigeo Sasaki ◽

Hiroyasu Shimizu

Keyword(s):

High Pressure ◽

Raman Study

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From Slater to Mott physics by epitaxially engineering electronic correlations in oxide interfaces

npj Computational Materials ◽

10.1038/s41524-021-00563-z ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Carla Lupo ◽

Evan Sheridan ◽

Edoardo Fertitta ◽

David Dubbink ◽

Chris J. Pickard ◽

...

Keyword(s):

Phase Diagram ◽

High Pressure ◽

Charge Transfer ◽

Lower Mantle ◽

Random Structure ◽

Titanium Oxides ◽

Oxide Interfaces ◽

Electronic Correlations ◽

Epitaxial Strain ◽

Magnetic Switching

AbstractUsing spin-assisted ab initio random structure searches, we explore an exhaustive quantum phase diagram of archetypal interfaced Mott insulators, i.e. lanthanum-iron and lanthanum-titanium oxides. In particular, we report that the charge transfer induced by the interfacial electronic reconstruction stabilises a high-spin ferrous Fe2+ state. We provide a pathway to control the strength of correlation in this electronic state by tuning the epitaxial strain, yielding a manifold of quantum electronic phases, i.e. Mott-Hubbard, charge transfer and Slater insulating states. Furthermore, we report that the electronic correlations are closely related to the structural oxygen octahedral rotations, whose control is able to stabilise the low-spin state of Fe2+ at low pressure previously observed only under the extreme high pressure conditions in the Earth’s lower mantle. Thus, we provide avenues for magnetic switching via THz radiations which have crucial implications for next generation of spintronics technologies.

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