| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Magnetic and optical properties of 1B metals produced radiation-chemically by reducing their mono cations in condensed matters have been investigated as a fundamental research to elucidate the function and effects of metal ions and/or metal atoms in biological systems.
Au^0 was produced at 77 K by γ-irradiation of MTHF solutions containing Au^+. The absorption bands at around 270-280 nm and 340 nm were ascribed to Au^0 in the solid solutions. The weak absorption band at around 420 nm was also attributed to Au^0. These bands were red-shifted and broadened compared to those in the rare gas matrixes, indicating a strong solvent-Au^0 interaction. Excitation of the absorption bands with light of wavelengths of 280 nm led to phosphorescence of three kinds of lifetimes. One of them with lifetime of about 625 ms was attributed to type of exciplex as (Au^+・Ln)^*. As for other two oomponents with lifetime of about 146 and 461 ms, it became clear from the behavior of the time dependence profile of
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the phosphorescence intensity that the latter grew as the former decayed. These were ascribed to such types of exciplex as (Au^0・Ln …Au^+)^* and (Au^+…Ln・Au^0)^*, respectively. The absorption band, which was ascribed to a photoionization of Au^0, must be around at 280 nm. The fluorescence band observed at 385 nm and a set of bands at 480, 520 and 580 nm bear close resemblance to the E_1 and E_2 bands of Ag^0, respectively. The former was attributed to the exciplex (Au^0・Ln …Au^+)^* that was not paramagnetic species. The latter was attributed to the exciplex (Au^0・Ln)^*. A group of the emission bands with peaks at 456, 482, 484 and 520 nm which had the characteristic structure of the minor image relations with the absorption bands of Au^0, in the gas phase and the solid rare gas phase. This structural profile was observed for the first time in the present study for Au^0 produced in γ-irradiated organic solid solutions at 77 K. These were attributed to Au^0 trapped in a large cavity where Au^0 in its excited state interacts very weakly with the surrounding solvent molecules. Less
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