[en] Primary processes of hot atom production initiated by nuclear transformation were discussed from past studies using Moessbauer spectroscopy. Many insulators (dielectric substances) showed various effect, such as abnormaly oxdized condition, following nuclear disintegration within the time duration of the life of Moessbauer nuclear excited state. Supposing these hot atom processes belonged to radiochemical processes, radiochemical characteristics of a certain chemical substance could be clarified by placing Moessbauer nuclide in the neighbourhood of the chemical substance to be studied. Chemical effects of disintegrated atom in the first and second composition, chemical substances produced in the surroundings of disintegrated atom, and environmental disturbance of disintegrated atom were studied and discussed. (Tsukamoto, Y.)

[en] Typical experimental results which demonstrate the applicability of Moessbauer spectroscopy to the studies of mixed-valence states of iron atoms are described, especially on biferrocenium and disubstituted biferrocenium salts, which show essentially no appreciable line-broadening at temperatures where the valence-state changes from a trapped to an averaged valence state. The Moessbauer spectroscopic data are compared with some of the results of X-ray crystal structure measurements. An order-disorder transition in valence-state is suggested as one of the plausible explanations for the temperature dependence of the Moessbauer spectrum. Suggestive results of the studies on oxo-centered trinuclear iron carboxylate complexes are also briefly mentioned. (orig.)

[en] The study of ammine cobalt complex by luminescent Moessbauer spectrometry method was performed. The method was compared with hot atom chemistry method. The electron states in atoms are changed by the aftereffect on Auger emission following the electron capture process. The state of oxidation of disintegration products is usually higher than that of parent nuclei. However, sometimes, lower oxidation is seen in Fe-57, the daughter nuclei of Co-57. This phenomenon may be due to radiation chemistry process, and this effect can be observed by the luminescent Moessbauer spectrometry method. However, the range of the effect can not be seen by the Moessbauer method. Estimation showed that the Auger electrons stay within the surrounding area of the disintegration atom, and the effect does not reach to distant places. The yield of Fe-57 in the electron capture process of Co-57 in cobalt complex, the G-value, and the hot atom chemical yield were obtained. It is concluded that the aftereffect of the Auger process is the localized radiation chemistry effect. Good correlation was seen between the present method and the hot atom chemistry method. (Kato, T.)

[en] Inner-shell ionization, internal conversion and Auger processes should be expected to leave the molecule with a very high positive charge. A Br(H₂O)^- ion was used as a hydrogen bonding system, and the electronic structure of the Br(H₂O)ⁿ⁺ ion produced after the inner-shell vacancy was calculated using an ab initio MO method. The distribution of the highly positive charges over all atoms in the ion was obtained. The repulsion energies between Br^m+ and H₂O^(n-m)+ were evaluated by the Coulomb repulsion among the positive atoms (Coulomb explosion model) and compared with those theoretically obtained by the use of the potential energy curve of the Br(H₂O)ⁿ⁺ ion. With an increase in the positive charge n, Coulomb explosion model was found to be well applicable to the decomposition of the Br(H₂O)ⁿ⁺ ion. The most abundant Brⁿ⁺ ion, which will be produced after the inner-shell vacancy of Br(H₂O)^-, was estimated to be Br³⁺ by the use of the experimental data on the charge distribution of Brⁿ⁺ following the X-ray irradiation. (author)

[en] Seven new compounds with the Sn-Mn bond have been prepared by carbonyl displacement with a weaker π-accepting ligand, L (L=P(C₆H₅)₃, As(C₆H₅)₃, Sb(C₆H₅)₃ for R₃Sn-Mn(CO)₅) or by reaction of the anion [Mn(CO)₅]^- or [Mn(CO)₄P(C₆H₅)₃]^- with R₃SnX (R=C₂H₅, n-C₃H₇, n-C₄H₉). A transconfiguration is deduced for the mono-substituted compounds, R₃Sn-Mn(CO)₄L, on the basis of the infrared spectra in the ν(CO) region. The ¹¹⁹Sn-Moessbauer and IR spectra are measured for sixteen compouns of the R₃Sn-Mn(CO)sub(5-n)Lsub(n) type (R=CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, Cl, Br, I; L=P(C₆H₅)₃, As(C₆H₅)₃, Sb(C₆H₅)₃; n=0 or 1). Both the Moessbauer-isomer shift and the quadrupole splitting increase with an increase in the length of the alkyl chain attached to the tin atom. The replacement of CO on the manganese atom with the weaker π-accepting ligand, L, has a significant effect on the isomer shift and quadrupole splitting of the tin atom through the sigma-and π-interaction between the tin and manganese atoms. An interpretation of the change in the chemical shift of the terminal methyl protons is also given for alkyl derivatives. (author)

[en] Mixed-valence states of biferrocene derivatives having long alkyl chains such as ditetradecyl, dihexadecyl, and dioctadecyl substituents were investigated. A little shortening in the inter-layer length by recrystallization from CH₂Cl₂ was observed in ditetradecyl and dihexadecyl derivatives, while no difference was observed in dioctadecyl derivative. Samples having a longer inter-layer length showed a temperature independent trapped-valence state. On the other hand, samples having a shorter inter-layer length showed a temperature dependence, in which two doublets observed at 80 K approach each other with an increase of temperature to converge into one doublet which is ascribed to an averaged-valence state. The results obtained in the present study prove the fact that the crystal structure affects the mixed-valence states. (orig.)

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[en] The Moessbauer parameters of bis(tri-n-butyltin) sulfate, selenate, and chromate have been determined in order to elucidate the intermolecular interaction of such species in solid state. The absolute values of recoilfree fraction have been estimated in the temperature range from 80 to 200 K and the mean square displacement of tin atom has been determined. From the results, as well as from the temperature dependence of quadrupole split line asymmetry, non-polymeric structure is inferred for those three compounds. (auth.)

No abstract available