Knowledge Bank

The luminescence induced by high-energy electron irradiation of frozen methylated benzenes has been studied. The visible band of benzyl-type radicals appears in the region of $470-520m\mu$. These are identical to the emission bands which have been thoroughly studied by Johnson and Albrecht recently. The spectrum of the benzyl radical was calculated by the method of configuration-interaction using several different approximations. Calculations employing only a few singly-excited configurations are in poor agreement with the data. When all singly-excited configurations are employed, reasonable agreement is achieved, in regard to both excitation energies and the symmetries of the excited states. For the several different approximations employed, ground-state $\pi$-orbital spin densities have also been calculated and compared with earlier results.