Summary
The optical spectra of Os(+4) and Ru(+4) in single cubic crystals of K2PtCl6 and Cs2ZrCl6 at 4.2 degrees K is reported. The results are analysed in terms of a complete d4 intermediate coupling scheme. Magnetic susceptibilities were calculated and the magnetic moments for all excited states were calculated. A report on a calculation of the intensities for these materials is included. Tables of wavefunctions and magnetic moments for the d4 system are given. (Author).