= Siegbahn precision X-ray wavelength spectroscopy
{c}
Precision <X-ray emission spectroscopy> turns closely spaced <spectral lines> into quantitative constraints on atomic <energy levels>. <Bragg's law> makes a <crystal> an angular ruler for <wavelength>: resolving nearby directions can reveal components hidden inside an apparently single line. Accurate line positions and the ability to separate two lines are related, but distinct, experimental achievements.
<Karl Manne Georg Siegbahn> received the 1924 <Nobel Prize in Physics>; his lecture was delivered on 11 December 1925.<Nobel Lectures, Physics 1922–1941/The X-ray Spectra and the Structure of the Atoms by Karl Manne Georg Siegbahn>[Nobel Lectures, Physics 1922–1941; The X-ray Spectra and the Structure of the Atoms, heading, printed p. 81]{ref}
His son <Kai Siegbahn> received the 1981 <Nobel Prize in Physics> for electron <spectroscopy>.<Facts on the Nobel Prize in Physics by Nobel Prize Outreach>[Family Nobel Prize laureates in physics, Father and son: Manne and Kai Siegbahn]{ref}
The <Barkla characteristic X-ray experiment> distinguished element-dependent K and L groups through absorption and excitation. <Moseley's law> related corresponding line <frequencies> across <chemical elements> to <atomic number>. Measuring the components within those groups asks a further question: which distinct atomic <energy> differences produce the neighbouring <spectral lines>?
Siegbahn's lecture organizes measured <spectral lines> into <energy levels> and resolved double levels.<Nobel Lectures, Physics 1922–1941/The X-ray Spectra and the Structure of the Atoms by Karl Manne Georg Siegbahn>[Nobel Lectures, Physics 1922–1941; Printed pp. 84–86, Figs. 1–2]{ref} The payoff is a map of atomic <energy> differences as well as an element's position in the <periodic table>.
Back to article page
