ELECTRON NUCLEAR DOUBLE RESONANCE IN AN ORGANIC MOLECULE IN A TRIPLET GROUND STATE . SPIN DENSITIES AND SHAPE OF DIPHENYLMETHYLENE MOLECULES IN DIPHENYLETHYLENE SINGLE CRYSTALS

The electron nuclear double resonance spectra of the protons in diphenylmethylene molecules in the ground triplet state in a single crystal of 1, l-diphenylethylene have been studied. The values, in the fine structure principal axis system, of the components of the proton-electron hyperfine interaction tensor have been determined and tabulated. Both the values of the 7 distinguishable spin densities and the molecule geometry, which give best fit to the measurements, have been given. Calculations made by the method of intermediate neglect of differential overlap have been compared with the experimental results.