= Léon Rosenfeld
{c}
{tag=Physicist}
{wiki}
<Léon Rosenfeld> and <Christian Møller> related the observed <electric quadrupole moment> of the <deuteron> to orientation-dependent <nuclear forces>. A purely spherical <charge distribution> gives zero quadrupole moment, because averaging $3z^2-r^2$ over directions cancels. A measured nonzero value therefore constrains the internal <quantum state> and the angular dependence of the interaction. Their 1939 work used this small electrical observable to test descriptions of the force between a <proton> and a <neutron>.<The Electric Quadrupole Moment of the Deuteron and the Field Theory of Nuclear Forces by Christian Møller and Léon Rosenfeld>[1939 abstract, deuteron quadrupole moment and orientation-dependent forces; spherical-average observation explained here]{ref}
\Image[https://commons.wikimedia.org/wiki/Special:Redirect/file/Rosenfeld,Leon_1963_Kopenhagen-a.jpg?width=260]
{title=Portrait of <Léon Rosenfeld>}
{description=GFHund. https://creativecommons.org/licenses/by/3.0/[CC BY 3.0], via Wikimedia Commons.}
{source=https://commons.wikimedia.org/wiki/File:Rosenfeld,Leon_1963_Kopenhagen-a.jpg}
{width=260}
Back to article page
