AbstractThe ultraviolet absorption spectra of benzophenones show well‐defined steric effects arising fromortho‐substitutions.In this paper the experimental data are given for a series of 12 methylsubstituted ketones, including benzophenone.From these data the oscillator strengthsfwere calculated for the C‐bands; mutual comparison of thesef‐values gives and idea of the magnitude of the steric effects caused byortho‐substituted meth