Knowledge Bank

Magnetic circular dichroism solution spectra of Cr(III), Co(III), Rh(III), and Ir(III) molecules trigonally surrounded by diethyldithiohosphate, diethyldithiocarbamate, and diethylxanthate were obtained in fields between 39 000--43 000 Gauss. Several E ($D3$) states were found to contain sufficient orbital angular momentum to have A-terms dominate the net rotations of d-d transitions. Spin-forbidden transitions of Cr(III), Rh(III) and Ir(III) compounds were decidedly more distinct and better resolved than in their electronic spectra. This effect is especially prominent for Cr(III) spectra. In fact, in several spectral regions of Cr(III) the MCD resolution of $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Gamma \to 2\Gamma$ transitions rivals that of $4\circ K$ electronic absorption data. The spectra and computer extracted molecular integral Faraday parameters will be reported and discussed in terms of their pertinence to electronic excited state properties.