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The magnetic circular dichroism of benzene, triphenylene, and coronene in regions of π→π absorption (20 000-45 000 cm−1) are reported. The data support the conventional molecular-orbital assignments of the absorption spectra. The lowest E′1 and E1u1 states of triphenylene and coronene, respectively, are shown to be little affected by Jahn-Teller perturbations. Magnetic moments are obtained for these states which are in good agreement with values calculated from the free-electron network model and from molecular-orbital wavefunctions if Löwdin orthogonalized atomic basis functions are employed.

Measurements of the magneto-optical rotatory dispersion (MORD) and magnetic circular dichroism (MCD) through the accessible charge-transfer bands of Fe(CN)63−, MnO4−, and CrO42− in the visible and ultraviolet are described and interpreted. The apparatus employed combines a superconducting solenoid furnishing maximum fields of 45 000 G with a commercial ORD—CD instrument which covers the range 185–700 mμ. The MCD measurements are found to be more reliable and are much easier to make; they are also more useful for theoretical interpretation. However, Kramers—Kronig transforms of the MORD results agree well with the experimental MCD measurements. Comparison of the theoretically derived Faraday parameters for Fe(CN)63− with those extracted from experiment shows that the 24 000-, 33 000-, and 38 500-cm−1 bands are due, respectively, to 2T2g→2T1u, 2T2u and 2T1u, ligand-to-metal(t2g) charge-transfer transitions. A similar analysis confirms the assignment of the lowest band in MnO4− and CrO42− to a t1(π)→e(π) transition. The observed parameters for higher bands agree well with predictions based on the recent Wolfsberg—Helmholz calculation of Viste and Gray but do not unambiguously confirm their assignments.

Hydrogen atom -hydrogen atom scattering is a prototype for many of the fundamental principles of atomic collisions. In this work we present the formalism

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