Photoemission Measurement on NaCl in the Photon Energy Range 32-50 eV

Photoemission measurements with photon energies ranging from the onset of Na $2p$ electron absorption to 50 eV have been performed using synchrotron radiation as a light source. The results indicate that the rise in the absorption coefficient starting at about 8.5 eV above the onset of $2p$ electron transitions is due to continuum transitions, whereas in the region below, most of the structures turn out to be exciton excitations.