The MIV, VSpectra of⁶⁸Er

The MIV and MV absorption spectra of Er2O3 have been studied in detail and a careful comparison made with the M?, ? emission lines. The MV absorption spectrum possesses a number of well-defined absorption maxima. It is shown that the minima between these maxima coincide closely with components of the M? multiplet and it is suggested that the main components of the emission line previously observed by Van der Tuuk and by Lindberg are not real but are produced by self-absorption in the target material The line is probably accompanied by one or more real satellites however. The MIV absorption spectrum is much weaker, but probably possesses a number of maxima also. The M? emission line probably possesses a satellite, but its form appears to be influenced by self-absorption.