The X-Ray<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>K</mml:mi></mml:math>-Absorption Edge for Sodium and the Secondary Structure Accompanying the Edge for the Sodium Halides

Abstract

A high vacuum, curved-crystal spectrograph was constructed for study of the $K$-absorption edge and the accompanying secondary absorption structures for evaporated films of sodium metal and of the sodium halides. Comparison of the $K{\ensuremath{\beta}}_{x}$ emission line and the $K$-absorption edge for metallic sodium indicates that the $K{\ensuremath{\beta}}_{x}$ line is not semi-optical in origin, but represents a transition from the ${M}_{\mathrm{II}\mathrm{III}}$ valence shell. The energies of the $1s$, $2p$, and $3p$ electron energy levels for metallic sodium are calculated. The energy difference between the $K{\ensuremath{\beta}}_{1}$ emission line and the $K$-absorption edge for ${\mathrm{Na}}^{+}$ in NaCl is found to be 5 ev greater than the difference between the $K{\ensuremath{\beta}}_{5}$ emission line and the $K$-absorption edge for ${\mathrm{Cl}}^{\ensuremath{-}}$ in NaCl. Strong secondary absorption patterns are found on the short wave-length side of the $K$-absorption edge for ${\mathrm{Na}}^{+}$ in the sodium halides. The distances from the various maxima and minima in the pattern to the main edges are correlated with the lattice distances and satisfactory agreement with Kronig's hypothesis is found except for the features near the main edge in the spectrum for NaF. Fair agreement is also found in comparison of these patterns with the patterns accompanying the $K$-absorption edge for ${\mathrm{K}}^{+}$ in the potassium halides, as determined by Brewington.