Quadrupole Interactions in Dilute Alloys

A class of novel hyper-crosslinked microporous polymers, based on green and renewable carbohydrates, was synthesized for carbon capture and storage with high CO2/N2 selectivity by hydrogen bonding and dipole–quadrupole interactions.

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Molecular packing in crystals of the aromatic hydrocarbons

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1965.0132 ◽

1965 ◽

Vol 286 (1404) ◽

pp. 98-116 ◽

Cited By ~ 65

Keyword(s):

Van Der Waals ◽

Equilibrium Structure ◽

Group Symmetry ◽

Structural Variations ◽

Angular Variation ◽

Coupling Energy ◽

Quadrupole Interactions ◽

Quadrupole Coupling ◽

Cell Dimensions ◽

Unit Cell Dimensions

The van der Waals energy, quadrupole-quadrupole coupling energy, and hydrogen-hydrogen repulsions have been calculated for the equilibrium structure of crystalline naphthalene and for several displaced structures. The displacements are small rotations of the molecules about their symmetry axes, phased so that the space-group symmetry and unit-cell dimensions are preserved. For structural variations of this type the hydrogen-hydrogen repulsions have a strong minimum within a few degrees angular variation from equilibrium, indicating that these repulsions are dominant and determine the crystal structure for this class of displacement. The attractive van der Waals and quadrupole interactions on the other hand are not minimized at the equilibrium structure; they vary slowly (by a few wavenumbers per degree rotation) and approximately linearly.

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Nuclear Gamma Resonance Study of the Ir —Fe and Ir —Ni Alloy Systems

Zeitschrift für Naturforschung A ◽

10.1515/zna-1971-0303 ◽

1971 ◽

Vol 26 (3) ◽

pp. 343-352 ◽

Cited By ~ 6

Author(s):

R.L. Mössbauer ◽

M. Lengsfeld ◽

W. Von Lieres ◽

W. Potzel ◽

T. Teschner ◽

...

Keyword(s):

Composition Range ◽

Magnetic Hyperfine Field ◽

Band Model ◽

Hyperfine Fields ◽

Ni Alloys ◽

Dilute Alloys ◽

Ni Alloy ◽

Bulk Magnetization ◽

Bcc Phase ◽

Alloy Systems

Abstract The Ir-Fe and Ir-Ni alloy systems were studied over the whole composition range by means of the nuclear resonance absorption of the 73 keV y-rays of 193Jr and of the 14.4 keV y-rays of 57Fe. The magnetic hyperfine field at the Ir-nuclei in Ir-Ni alloys decreases approximately linearly with the Ir concentration from - 460 kOe at 4.2 K in very dilute alloys to zero at about 20 at.-% Ir. This behaviour is paralleled by the decrease of the magnetic moment per Ni atom as determined from bulk magnetization measurements. The hyperfine fields at both Ir and Fe were measured for the ferromagnetic bcc phase of the Ir-Fe system. They turned out to be virtually independent of concentration with values of about -1400 kOe and - 330 kOe, respectively. Linewidths increasing with the Ir concentration indicate a distribution of hyperfine fields. The fee phase of the Ir-Fe system has been found to be paramagnetic at 4.2 K throughout the range of its existence. The dependence of the hyperfine fields on concentration is discussed in terms of a rigid 3d-band model combined with local shielding. A discussion of the concentration dependence of the 193Ir and 57Fe isomer shifts has to take into account lattice expansion as well as band repopulation effects.

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