SIMULTANEOUS EXCITATION OF 2 ELECTRONS IN ATOMIC CADMIUM

A new investigation of the Cd I absorption spectrum, with an electron synchrotron as a background continuum source, has revealed 110 new features. All are attributable to simultaneous excitation of two electrons, observed for the first time in cadmium. At longer wavelengths the spectrum is due to the excitation of both valence electrons and at shorter wavelengths it is due to excitation of one valence, and one 4d-subshell electron. The detailed analysis suggests that, as in zinc, double-excitation occurs through a final state configuration mixing process similar to conjugate shake-up.