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Abstract: In order to directly observe the effect of daughter product formation on the stability of a crystalline compound, 55Fe was produced at the Isotope Production Facility at Los Alamos National Laboratory. After purification, the metal was oxided to 55Fe2O3. Samples were loaded in diamond anvil cells, with neon as a pressure transmitting medium, and pressurized to pressures between 5 and 15 GPa. The samples were then characterized by synchrotron powder diffraction and micro-Raman spectroscopy. The present study serves as a reference for future studies, in which the formation of 55Mn2O3 from 55Fe2O3 by radioparagenesis will be explored. [Copyright &y& Elsevier]

The first lanthanide dinitrogen photoswitch [(C 5 Me 4 H) 2 (THF)Lu] 2 (μ-η 2 :η 2 -N 2 ), 1 , is reported. 1 is a unique example of controlled isomerization between side-on and end-on coordination modes of [N 2 ] 2- in a bimetallic lutetium dinitrogen complex that results in photochromism. Near-infrared light (NIR) was used to promote this effect, as evidenced by single X-ray diffraction (XRD) connectivity and Raman data, generating the [N 2 ] 2- end-on bound isomer, [(C 5 Me 4 H) 2 (THF)Lu] 2 (μ-η 1 :η 1 -N 2 ), 2 . Although different ligands and coordinating solvents were studied to replicate and control the optical properties in 1/2 , only the original configuration with C 5 Me 4 H ligands and THF as the coordinating solvent worked. Supported by the first-principles calculations, the electronic structures along with the mechanistic details of the side-on to end-on isomerization were unraveled. Preliminary reactivity studies show that 2 formed with NIR light reacts with anthracene, generating dihydroanthracene and anthracene dimers, indicating new redox reaction pathways.

Cross sections for the formation of (225,227)Ac, (223,225)Ra, and (227)Th via the proton bombardment of natural thorium targets were measured at a nominal proton energy of 800 MeV. No earlier experimental cross section data for the production of (223,225)Ra, (227)Ac and (227)Th by this method were found in the literature. A comparison of theoretical predictions with the experimental data shows agreement within a factor of two. Results indicate that accelerator-based production of (225)Ac and (223)Ra is a viable production method., (Published by Elsevier Ltd.)

Cross sections for (223,)(225)Ra, (225)Ac and (227)Th production by the proton bombardment of natural thorium targets were measured at proton energies below 200 MeV. Our measurements are in good agreement with previously published data and offer a complete excitation function for (223,)(225)Ra in the energy range above 90 MeV. Comparison of theoretical predictions with the experimental data shows reasonable-to-good agreement. Results indicate that accelerator-based production of (225)Ac and (223)Ra below 200 MeV is a viable production method., (Published by Elsevier Ltd.)