INTERDOUBLET TRANSITIONS IN S = 5 2 PROTEIN SYSTEMS/

Beginning with known parameters that characterize the EMR spectra of s everal proteins containing high-spin ferric iron, the information cont ent of the spectra has been examined by simulations that cover a range of magnetic fields and frequencies, Transitions between levels that a re not Kramers doublet levels are particularly interesting when the ap plied frequency is approximately two to three times the value of the z ero-field splitting parameter, D. In these cases, transitions al very low magnetic fields correspond to portions of interdoublet transitions that are well separated from all other transitions. The magnetic fiel d is aligned at angles between the molecular principal axes for the po rtion of the molecules giving rise to the low-field interdoublet trans itions. This provides an opportunity for unique angle-selection experi ments. (C) 1997 Elsevier Science B.V.