Quadrupole Interaction

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Quadrupole Interaction

 

the interaction of systems of charged particles widely separated from one another, defined by the presence in the systems of what is called a quadrupole moment. If the electric charge or the dipole moment of a system differs from zero, the quadrupole interaction can usually be neglected.

The energy of quadrupole interactions for atoms (which have no dipole moment) falls off with the distance R by 1/R5, while the energy of the interaction of the dipole moments induced in these atoms by their mutual polarization varies with distance by 1/R6. Therefore, the quadrupole interaction of atoms is predominant at large distances. The quadrupole moment of atoms can be computed by means of quantum mechanics.

Many atomic nuclei in which the electric charge distribution does not have spherical symmetry have a quadrupole moment. Quadrupole interaction plays an important role in nuclear physics when a nucleus with zero dipole moment is excited by the coulomb field of charged particles bombarding it. Nuclear quadrupole moments are determined experimentally.

G. IA. MIAKISHEV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The [gamma]-[gamma] cascade at (133-482) keV, populated by the [beta]-decay of 181 Hf, was used to measure the quadrupole interaction of the 482 keV (+5/2) state of [sup.181]Ta.
The [G.sub.22] (t), the perturbation function, for a static quadrupole interaction has the following expression:
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The quadrupole interaction is a just theoretical artifact so far, he admits, but it explains the appearance of forbidden bands arising in a great number of experiments on symmetrical molecules with surface enhanced Raman scattering (SERS).
The large size of the nuclear quadrupole interaction (typically on the order of [10.sup.6] Hz) is just one of the reasons it is difficult to record NMR spectra of such nuclei with high resolution.
Key words: atomic polarizabilities; electric quadrupole interaction; mercury ion; optical frequency standards; Stark shift; Zeeman shift.
Nuclei with a spin I = 1/2 lose their polarization by dipole-dipole interactions during collisions with walls or with each other, while nuclei with a spin I > 1/2 have an additional loss by electric quadrupole interactions. [.sup.131]Xe nuclei are used as a polarized target, while the other noble gas nuclei with I [not equal to] 0 may be used for the compensation of the pseudomagnetism.