Nuclear Quadrupole Moment

nuclear quadrupole moment

[′nü·klē·ər ′kwäd·rə‚pōl ‚mō·mənt]

(nuclear physics)

The electric quadrupole moment of an atomic nucleus.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

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 It might be outdated or ideologically biased.

Nuclear Quadrupole Moment

 

the quantity thatcharacterizes the deviation from spherical symmetry of the elec-trical charge distribution in an atomic nucleus. It has the dimen-sion of area and is usually expressed in sq cm. For sphericalsymmetry the nuclear quadrupole moment Q = 0. If a nucleusis extended along the axis of symmetry, then Q is a positivequantity, but if the nucleus is flattened along the axis, it isnegative. The value of the nuclear quadrupole moment variesover a wide range. For example, the nucleus of O, Q = -0.027 X 10^-24 sq cm; for the nucleus of Am Q = +14.9 X 10^-24 sq cm. Large moments are usually positive. Thismeans that when there is a substantial deviation from sphericalsymmetry, the nucleus has the shape of an elongated ellipsoid ofrotation.

V. P. PARFENOVA

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.