| Abstract: | The present article is concerned with theoretical consideration of the effect of oxygen diffusion on the relaxation parameters of paramagnetic centers (PC) located on a surface. Proceeding from a model of dipole-dipole interaction between paramagnetic molecules of O2 and PC that is modulated by translational diffusion motion of O2 molecules in the volume and on surface of an adsorbent and in its pores, we give an explanation for the observed dependence of the intensity of the EPR signal on the pressure of O2. In the present case, diffusion in the volume is the decisive factor. We also managed to explain the presence of an SHF field power threshold for the indicated phenomenon to be observed. In the calculations we used correlation functions obtained earlier for diffusion in a volume. Institute of Physicoorganic Chemistry, National Academy of Sciences of Belarus, 13, Surganov St., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 230–235, March–April, 1998. |
