scholarly journals Phase separation near the charge neutrality point in FeSe1-xTex crystals with x < 0.15

2021 ◽  
Author(s):  
Yevgeniy Anatolevich Ovchenkov ◽  
Dmitry Chareev ◽  
Ekaterina S. Kozlyakova ◽  
Eduard Levin ◽  
Mihail G. Miheev ◽  
...  
Keyword(s):  
Phase Separation ◽  
Crystal Field ◽  
Structural Instability ◽  
Phenomenological Description ◽  
Layered Compounds ◽  
Significant Component ◽  
Magnetic Exchange ◽  
Bond Polarity ◽  
Charge Neutrality ◽  
D Orbitals

Abstract Our study of FeSe$ _ {1-x}$Te$ _ {x}$ crystals with x $<$ 0.15 shows that the phase separation in these compositions occurs into phases with a different stoichiometry of iron. This phase separation may indicate structural instability of the iron plane in the studied range of compositions. We tentatively propose an explanation of the structural instability of the iron plane in the studied layered compounds in terms of the possible change in the bond polarity and the peculiarity of the direct $d-d$ exchange in the iron plane in the framework of the basic phenomenological description such as the Bethe-Slater curve. With this approach, when the distance between iron atoms is close to the value at which the sign of the magnetic exchange for some $d$ orbitals changes, structural and electronic instability can occur. Anomalies in the crystal field near the point of charge neutrality can also be a significant component of this instability.

scholarly journals Assessing crystal field and magnetic interactions in diuranium-μ-chalcogenide triamidoamine complexes with UIV–E–UIV cores (E = S, Se, Te): implications for determining the presence or absence of actinide–actinide magnetic exchange

2017 ◽  
Vol 8 (9) ◽  
pp. 6207-6217 ◽  
Author(s):  
Benedict M. Gardner ◽  
David M. King ◽  
Floriana Tuna ◽  
Ashley J. Wooles ◽  
Nicholas F. Chilton ◽  
...  
Keyword(s):  
Crystal Field ◽  
Exchange Coupling ◽  
Magnetic Interactions ◽  
Magnetic Exchange ◽  
Field Effects

Analysis of UIV–E–UIV (E = S, Se, Te) complexes reveals their behaviour is due to crystal field effects and not exchange coupling.

Electronic Structure of Octacyanides of Molybdenum IV and V According to the SCCC MO Method. The D2d Case

1972 ◽  
Vol 27 (11) ◽  
pp. 1672-1677 ◽  
Author(s):  
A. Gołębiewski ◽  
R. Nalewajski
Keyword(s):  
Field Theory ◽  
Electronic Structure ◽  
Crystal Field ◽  
Central Atom ◽  
Molecular Orbitals ◽  
Crystal Field Theory ◽  
D Orbitals

Abstract The electronic structure of dodecahedral octacyanides of molybdenum IV and V is described in terms of SCCC molecular orbitals. Five MO's resemble d orbitals of the central atom. The splitting of appropriate levels is almost exactly the same as that following from the crystal field theory for G4/G2 ~ 0.7. According to the theory stable Mo(CN)84- is dodecahedral and stable MO(CN)83- is antiprismatic. In the dodecahedron the A-type ligands are bonded more strongly than the B-type ligands.

Crystal field splittings of continuum d orbitals. A comparative study on the L2,3 edge X-ray absorption spectra of Si, P and S compounds

1992 ◽  
Vol 168 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Z.F. Liu ◽  
J.N. Cutler ◽  
G.M. Bancroft ◽  
K.H. Tan ◽  
R.G. Cavell ◽  
...  
Keyword(s):  
Comparative Study ◽  
Crystal Field ◽  
Absorption Spectra ◽  
X Ray ◽  
X Ray Absorption ◽  
D Orbitals

Crystal-field theory for the Rydberg states of polyatomic molecules

1986 ◽  
Vol 64 (7) ◽  
pp. 782-795 ◽  
Author(s):  
Ying-Nan Chiu
Keyword(s):  
Crystal Field ◽  
Spherical Harmonics ◽  
Rydberg States ◽  
Second Order ◽  
Crystal Field Theory ◽  
Linear Combinations ◽  
Atomic Orbitals ◽  
Square Planar ◽  
Rydberg Electron ◽  
D Orbitals

The potential on a Rydberg electron due to the cluster of atoms near the center of a polyatomic molecule is expanded in powers of spherical harmonics. Nonvanishing potentials in totally symmetric irreducible representations are obtained using the crystal field of the cluster of atoms in D3h, C3v, D4v, C4v, Td, and D2d symmetries. Odd as well as the usual even powers of spherical harmonics are included up to [Formula: see text]. Spectroscopically observable differences in potentials between a planar versus a nonplanar XY3 molecule and among a square planar, pyramidal, tetrahedral, and dihedral XY4 molecule are exhibited. First-order energies are given for a Rydberg [Formula: see text] state showing λ dependence. Second-order energies due to mixing of Rydberg states by odd and even power potentials and splitting of ±λ degeneracies are shown analytically for an nd as well as an nf Rydberg electron. The formalism is applicable to nonpenetrating Rydberg orbitals. Approximate radial integrals are obtained. Exact angular integrals for the first- and second-order energies are given. Symmetry-adapted combinations of the separated Y3 and Y4 ligand atomic orbitals are derived up to d orbitals. The correlations between these linear combinations of atomic orbitals as molecular configurations change are shown, e.g., as an XY4 molecule distorts from (D4h, C4v) to (D2d, Td) and vice versa.

Notizen: Low Temperature Magnetic Susceptibility of Sm2(WO4)3

1975 ◽  
Vol 30 (12) ◽  
pp. 1783-1784 ◽  
Author(s):  
H.B. Lal ◽  
Naseeb Dar
Keyword(s):  
Magnetic Susceptibility ◽  
Low Temperature ◽  
Crystal Field ◽  
Low Temperatures ◽  
Magnetic Ordering ◽  
Magnetic Exchange ◽  
Temperature Range ◽  
Powder Samples

Abstract The magnetic susceptibility of powder samples of Sm2(WO4)3 has been measured in the temperature range 4.2 to 300 K. At low temperatures the measured values disagree with those calculated for Sm3+-ions using Van Vleck's theory. The high values below 100 K are assigned to magnetic exchange and dipol interactions. There might be magnetic ordering below 4.2 K. The effects of the crystal field and impurities have been shown to be unimportant.

scholarly journals Systematic investigation of the magneto-electronic structure and optical properties of new halide double perovskites Cs2NaMCl6 (M = Mn, Co and Ni) by spin polarized calculations

RSC Advances ◽  
2020 ◽  
Vol 10 (44) ◽  
pp. 26277-26287 ◽  
Author(s):  
Shabir Ahmad Mir ◽  
Dinesh C. Gupta
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Crystal Field ◽  
Systematic Investigation ◽  
Double Perovskites ◽  
Half Metallicity ◽  
Spin Polarized ◽  
Unpaired Electrons ◽  
D Orbitals

The unpaired electrons in the crystal field splitted d-orbitals of the M-site constituents are responsible for the half metallicity and magnetic character of the halide double perovskites.

scholarly journals Macro- and Microphase Separated Protein-Polyelectrolyte Complexes: Design Parameters and Current Progress

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 578 ◽  
Author(s):  
Justin Horn ◽  
Rachel Kapelner ◽  
Allie Obermeyer
Keyword(s):  
Drug Delivery ◽  
Phase Separation ◽  
Food Processing ◽  
Design Parameters ◽  
Charge Neutrality ◽  
Polyelectrolyte Complexes ◽  
Overall Design ◽  
Potential Applications ◽  
Spherical Micelles ◽  
Oppositely Charged

Protein-containing polyelectrolyte complexes (PECs) are a diverse class of materials, composed of two or more oppositely charged polyelectrolytes that condense and phase separate near overall charge neutrality. Such phase-separation can take on a variety of morphologies from macrophase separated liquid condensates, to solid precipitates, to monodispersed spherical micelles. In this review, we present an overview of recent advances in protein-containing PECs, with an overall goal of defining relevant design parameters for macro- and microphase separated PECs. For both classes of PECs, the influence of protein characteristics, such as surface charge and patchiness, co-polyelectrolyte characteristics, such as charge density and structure, and overall solution characteristics, such as salt concentration and pH, are considered. After overall design features are established, potential applications in food processing, biosensing, drug delivery, and protein purification are discussed and recent characterization techniques for protein-containing PECs are highlighted.

scholarly journals The influence of halides in polyoxotitanate cages; dipole moment, splitting and expansion of d-orbitals and electron–electron repulsion

2017 ◽  
Vol 46 (2) ◽  
pp. 578-585 ◽  
Author(s):  
Schirin Hanf ◽  
Peter D. Matthews ◽  
Ning Li ◽  
He-Kuan Luo ◽  
Dominic S. Wright
Keyword(s):  
Dipole Moment ◽  
Crystal Field ◽  
Electronic Structures ◽  
Theoretical Study ◽  
Crystal Field Splitting ◽  
Field Splitting ◽  
Electron Repulsion ◽  
D Orbitals

The influence of halides on the electronic structures of polyoxotitanate cages is explored in this experimental and theoretical study. Dipole moment, crystal-field splitting, Nephelauxetic influence of the halide and electron–electron repulsion all play a role.

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