Knowledge Bank

Emerald is $Cr3+$ doped beryl, and the $Cr3+$ ion lies on a site having approximately octahedral coordination of oxygen ligands. The crystal field levels of the $Cr3+$ ion have been previously reported in an analysis of the broad features of the spectrum. The red fluorescence lines $(2E\to A2)$ are sharp enough to partially resolve the Zeeman splitting with D.C. magnetic fields up to 31 kilogauss. The patterns are completely resolved in absorption $(4A2\to 2E)$ for very high fields (200 kilogauss) generated by pulse techniques. The patterns for both zero field and large field give a measure of the trigonal distortion of the octahedral site, the orbital reduction in the excited state, and the spin-orbit coupling parameter. These will be discussed after some brief comments on the production of large pulsed magnetic fields for spectroscopy.