= Friedrich Hund
{c}
{tag=Physicist}
{wiki}
<Friedrich Hund> organized complicated atomic <spectral lines> through relationships between the <angular momenta> and <energy levels> of many-<electron> configurations. In modern notation, a <term symbol> $^{2S+1}L_J$ records total <electron spin> $S$, total <orbital angular momentum> $L$ and coupled total <angular momentum> $J$. For example, $S=1$ permits three <spin projections>, whereas $S=0$ permits one. The classification reduces a large pattern of lines to relationships between fewer <quantum states>. This modern spin notation should be distinguished from the historical language of his original spectral analysis.<Zur Deutung verwickelter Spektren, insbesondere der Elemente Scandium bis Nickel by Friedrich Hund>[1925 spectral classification; modern notation explained here]{ref}
\Image[https://commons.wikimedia.org/wiki/Special:Redirect/file/Hund%2C%20Friedrich%201920er%20G%C3%B6ttingen.jpg?width=250]
{title=Portrait of <Friedrich Hund>}
{description=Original photographer unidentified; Friedrich Hund estate, held and supplied by Gerhard Hund (GFHund); existing border crop by Sebastian Wallroth. https://creativecommons.org/licenses/by/3.0/[CC BY 3.0], via Wikimedia Commons.}
{source=https://commons.wikimedia.org/wiki/File:Hund%2C_Friedrich_1920er_G%C3%B6ttingen.jpg}
{width=250}
Back to article page
