Dipolar Interaction in TEMPAD Biradical

The EPR of TEMPAD single crystals diluted in diamagnetic matrices was studied. The results of the 10% TEMPAD were almost the same as those of the very dilute one studied previously. In the case of the 25% TEMPAD, the spectra are composed of three parts. The central broad line, whose linewidth was analyzed in comparison with the pure TEMPAD case using the three-dimensional Anderson-Weiss formula, is the spectrum of clusters constructed by the free radicals. The side lines with the hyperfine splitting are the spectrum of the isolated TEMPAD molecule, and the outer broad lines are from the molecules coupled in pairs along the a-axis. The EPR spectra of the pure TEMPAD at very low temperature were also measured in order to have information concerning the dipolar interaction in the pure crystal. These spectra are the superposition of the spectra caused by the intra-molecular dipolar interaction and of the spectra due to impurities. All the results were explained with the suitable molecular stack model and the ...

[1]  V. Hepp,et al.  A measurement of radiative λ decays , 1972 .

[2]  Z. Soos,et al.  Electron Dipolar Linewidth of Single-Crystal TMPD Chloranil , 1972 .

[3]  A. Miedema,et al.  Antiferromagnetic Linear Chains in the Crystalline Free Radical BDPA , 1972 .

[4]  A. Nakajima,et al.  Magnetic Properties of Some Iminoxyl Polyradicals. III. Exchange Interaction in Iminoxyl Biradicals , 1972 .

[5]  A. Nakajima,et al.  Magnetic Properties of Some Iminoxyl Polyradicals. II. TEMPOP Triradical and TEMPOS Tetraradical , 1971 .

[6]  P. Fedders,et al.  Spin Susceptibilities of Organic Systems on a Narrow‐Band Model , 1970 .

[7]  T. Fujito,et al.  Magnetic Properties of Organic Stable Radicals. I. 2,2,6,6-Tetramethyl-4-Hydroxypiperidine-1-Oxyl , 1968 .

[8]  A. Nakajima,et al.  Anomalous Behavior of Paramagnetic Susceptibility of TEMPAD Biradical , 1968 .

[9]  R. C. Hughes,et al.  Magnetic Excitations in Charge‐Transfer Complexes. I. p‐Phenylenediamine–Chloranil , 1968 .

[10]  W. Duffy,et al.  Theory of Alternating Antiferromagnetic Heisenberg Linear Chains , 1968 .

[11]  H. Lemaire,et al.  Nitroxydes XXVII. Chaleur spécifique du tétra-méthyl-2,2,6,6 pipéridinol-4 oxyle-1 entre 1,3°K et 74°K , 1968 .

[12]  D. L. Strandburg,et al.  Paramagnetism of Carbazyl and Hydrazyl Free Radicals , 1967 .

[13]  R. C. Hughes,et al.  Paramagnetic Susceptibilities and Temperature‐Dependent Excitation Energies in Linear Organic Crystals , 1967 .

[14]  Z. Soos.  Theory of the Linear Heisenberg Antiferromagnet. Application to Paramagnetic Excitations in Organic Crystals , 1965 .

[15]  G. Pake,et al.  Linear Antiferromagnetism in the Organic Free Radical 1,3‐Bisdiphenylene‐2‐Phenyl Allyl , 1963 .

[16]  J. H. Waals,et al.  Paramagnetic resonance in phosphorescent aromatic hydrocarbons. I: Naphthalene , 1959 .

[17]  H. Gerritsen,et al.  Some magnetic properties of diphenyl trinitrophenyl hydrazine at low temperatures , 1954 .

[18]  P. Anderson,et al.  Exchange Narrowing in Paramagnetic Resonance , 1953 .