Noriko Yamazaki

OBSERVATION OF SURFACE DISTRIBUTION OF PRODUCTS BY X-RAY FLUORESCENCE SPECTROMETRY DURING D2 GAS PERMEATION THROUGH Pd COMPLEXES

In-situ measurement of transmutation of Cs into Pr was performed, and the surface distribution of Pr was investigated using XRF (X-Ray Fluorescence spectrometry) at SPring-8, a large synchrotron x-ray facility. The in-situ measurement indicated that Pr emerged and Cs decreased at some points after D2 gas permeation, though any Pr cannot be observed before D2 gas permeation at all the points on the Pd complex surface. Using small size X-ray beam in 100and 500-micrometer squares, we obtained 2 dimensional XRF spectra for three permeated samples, from which we detected Pr. Pr was detected again by the two small x-ray beams as expected. The amount of Pr varied greatly at different locations of the Pd surface, however, a clear correlation between surface structures and distribution of Pr has not seen up to now. Experimental results suggest that nuclear transmutations do not occur uniformly but some uncertain factors, presumably condensed matter effects in the present Pd/D/CaO system, have a large effect on the rate or the process of the reactions.

OBSERVATION OF NUCLEAR TRANSMUTATION REACTIONS INDUCED BY D2 GAS PERMEATION THROUGH Pd COMPLEXES

We have been studying low energy nuclear transmutations induced by D2 gas permeation through Pd complexes (Pd/CaO/Pd). We presented experimental results at ICCF9 and ICCF10 . In this paper, we report recent progress. Transmutations of Ba into Sm were observed in two cases: with natural Ba on Pd complex samples (a definite result), and with mass 137-enriched Ba (probable). In these experiments, the atomic mass increase was 12 and atomic number increase was 6. One of our experimental apparatuses was carried to SPring-8, which is the world’s largest synchrotron radiation facility, located at Hyogo prefecture in Japan. Pr was confirmed several times by XRF at SPring-8. Some experiments were done to explore physical structure of the CaO layer. According to a D ion beam bombardment experiment performed at Tohoku University, the deuterium density of our Pd complex is one order larger than normal Pd. When we replaced CaO with MgO, we did not obtain any positive results. These results shed light on the role of the CaO layer in the Pd complex.

Hydration structure of CO2-absorbed 2-aminoethanol studied by neutron diffraction with the 14N/15N isotopic substitution method.

Neutron diffraction measurements were carried out for CO2-absorbed aqueous 11 mol % 2-aminoethanol (MEA) D2O solutions (corresponding to 30 wt % MEA solution) in order to obtain information on both the intramolecular structure and intermolecular hydration structure of the MEA carbamate molecule in the aqueous solution. Neutron scattering cross sections observed for (MEA)0.11(D2O)0.89, (MEA)0.11(D2O)0.89(CO2)0.06, and (MEA)0.11(D2O)0.89(DCl)0.11 solutions with different (14)N/(15)N ratios were used to derive the first-order difference function, ΔN(Q), which involves environmental structural information around the nitrogen atom of the MEA molecule. Intramolecular geometry and intermolecular hydration structure of MEA, protonated MEA (MEAD(+)), and MEA carbamate (MEA-CO2) molecules were obtained through the least-squares fitting of the observed Δ(N)(Q) in the high-Q region and the intermolecular difference function, Δ(N)(inter)(Q), respectively. In the aqueous solution, the MEA molecule takes the gauche conformation (dihedral angle, ∠NCCO = 45 ± 3°), suggesting that an intramolecular hydrogen bond is formed. On the other hand, values of the dihedral angle ∠NCCO determined for MEAD(+) and MEA-CO2 molecules were 193 ± 4° and 214 ± 8°, respectively. These results imply that the intermolecular hydrogen bonds are dominated for MEAD(+) and MEA-CO2 molecules. The intermolecular nearest neighbor N···O(D2O) distance for the MEA molecule was determined to be 3.13 ± 0.01 Å, which suggests weak intermolecular interaction between the amino-nitrogen atom of MEA and water molecules in the first hydration shell. The nearest-neighbor N···O(D2O) distances for MEAD(+) and MEA-CO2 molecules, 2.79 ± 0.03 and 2.87 ± 0.04 Å, clearly indicate strong hydrogen bonds are formed among the amino group of these molecules and neighboring water molecules.