[en] Cation radicals of some aromatic hydrocarbons, aliphatic amines, and aromatic amines are produced by γ irradiation of frozen glassy solutions using organic halides as the solvent. The electronic absorption spectra of the cation radicals are compared with the photoelectron spectra of the parent molecules in order to find correlations between the two spectra. Complementary aspects of the two types of spectroscopy are discussed

[en] The reaction between rare earth oxides and elementary fluorine has been studied by means of thermogravimetric and kinetic measurements. La₂O₃, Pr₆O₁₁ and Tb₄O₇ violently react with fluorine gas even at room temperature to form trifluorides. The other twelve rare earth oxides begin to react at 260 deg C. CeO₂, Nd₂O₃, Sm₂O₃ and Eu₂O₃ are completely converted into trifluoride up to 550 deg C, but sesquioxides of Y, Gd and Dy through Lu are gradually fluorinated and the reactions are not complete even at 550 deg C. The fluorination process of Nd₂O₃ is discussed by dividing into three reaction stages. The neodymium oxide fluoride with the minimum fluorine composition is found to be NdOf and the fluorine-rich compositions can be expressed by Nd₄O_6-xF_2x, where 2< x<6

[en] Oxygenated 2-mehyltetrahydrofuran glasses containing maleic anhydride (MA) were γ-irradiated at 77 K followed by warming, and optical and ESR spectra were measured. Two species peculiar to the presence of both MA and O₂ were found: one that appears at earlier stages is characterizied by both a broad optical absorption band at 432 nm and an ESR band with g/sub z/ = 2.047, and the other that follows this possesses an optical band at 640 nm and an ESR band with g/sub z/ = 2.055. the features of the observed ESR spectra including those for ¹⁷O₂ indicate that these species are most likely molecular complexes, O₂^-...(MA) and O₂^-...(MA)₂, respectively. Similar optical and ESR spectra were also observed for methyl- and dimethylmaleic anhydride, maleimide, and fumaronitrile. 8 figures, 1 table

[en] The time evolution of optical absorptions of cationic species in sec-butyl chloride glasses at 77 K was observed over the range of 10^-5 to 1 s after irradiation with electron pulses. A band tail newly found at wavelengths shorter than 420 nm in a pure glass is assignable to a precursor of the trapped hole characterized by the 480-nm band. In the presence of an aromatic solute, trapped holes decay over the above time range and solute cations grow concurrently. In biphenyl-pyrene solutions, the decay of biphenyl cations is accompanied by the growth of pyrene cations. The observed positive-charge transfer is consistent with long-range electron transfer. 6 figures

[en] sec-Butyl chloride glasses containing amines were pulse radiolyzed at 77 K, and the time change of matrix holes was monitored over the time range of 3 μs to 1.7 s. Similar observation was made for glasses containing both amine and excess biphenyl, where biphenyl cations were monitored. The survival fraction of either matrix holes or biphenyl cations continued to decrease over several orders of magnitude of time. The rate of positive-charge transfer to amines increased with decreasing ionization potential of amine but did not differ for two positive-charge donors, matrix holes and biphenyl cations. The net process of the observed positive-charge transfer can be regarded as long-range electron transfer from amines. The dependence of the rate on the ionization potential of amines was explained by estimating the electronic interaction matrix element for long distance on the basis of elecron tunneling between two Coulombic traps

[en] Titanium dioxide was coated onto the pore wall surface of anodic alumina membranes from solution of titanyl (IV)acetylacetonate. After calcinations at various temperatures, the XRD analysis of each specimen indicated the anatase phase of titanium dioxide. The TiO₂ coated anodic alumina membranes were evaluated for the photocatalytic activity in the decomposition of salicylic acid. The membrane which coated by 40 wt% solution of titanyl(IV)acetylacetonate and calcined at 500 deg C showed the highest photocatalytic activity. Copyright (2003) AD-TECH - International Foundation for the Advancement of Technology Ltd

[en] Rates of electron transfers from trapped electrons to deuterated and protiated solute molecules were comparatively measured in 2-methyltetrahydrofuran glass at 77 K by the pulse radiolysis method. Similar measurement was done for electron transfers from solute molecules to trapped holes in sec-butyl chloride at 77 K. The compounds used were biphenyl, naphthalene, pyrene, acridine, nitrobenzene, and p-benzoquinone. The magnitude of deuteration effects on the rate did not exceed the experimental errors

[en] Recently, a table-top fs laser system can generate MW terahertz (THz) pulse with its electric field higher than 100 kV/cm can be generated by several schemes. Such a strong THz field can directly drive electrons inside various materials. Here, we demonstrated a direct THz electric field detection method by measuring the electroluminescence induced by intense THz pulse inside commonly available light emitting diode. An intense THz wave obtained by the two-color laser scheme was focused onto LED along with an external DC bias to induce luminescence which we found proportional to the amplitude of the incident THz field. The scheme can be useful to realize a low-cost, probe-free THz detection and imaging system. (paper)

[en] Highlights: • Sensitive electrochemical techniques were used to evidence the formation of Ag(III). • The required potential for the generation of Ag(III) was found by using UV–vis to monitor species being formed. • A mechanism for the production of Ag(III) in the form of Ag(OH)₄⁻ is proposed. -- Abstract: A mechanism based on electrochemical, spectrophotometric and scanning electron microscopy (SEM) data in alkaline media is proposed for the generation of Ag(III) in the form of Ag(OH)₄⁻. The formation of Ag(III) from Ag⁰ is a rather complex multistep process that involves several steps. The presence of soluble Ag(I) species as Ag(OH)₂⁻ is of paramount importance for the production of soluble Ag(OH)₄⁻, whose decomposition time is shown to exceed 8 h