Controversy on the First Ionization Potential of PuO2 (Nearly) Settled by New Experimental Evidence

Very high temperature laser heated furnace for Knudsen cell mass spectrometry

A very high temperature furnace (up to 3000 degrees C) for the Knudsen cell mass spectrometry (KCMS) based on a laser heating technique has been developed. It is demonstrated that this system overcomes some of the typical technological problems encountered by the standard methods and can be more easily handled in special environments such as gloveboxes or hot cells. This paper describes the laser heated KCMS general design. The technology of the laser furnace along with its advantages, disadvantages, and applications is presented. Mechanical designs, some technical details, and the importance of the temperature control are also discussed.

The heat of formation of gaseous PuO22+from relativistic density functional calculations

Using a set of model reactions, we estimated the heat of formation of gaseous PuO2(2+) from quantum-chemical reaction enthalpies and experimental heats of formation of reference species. To this end, we carried out relativistic density functional calculations on the molecules PuO(2)2+, PuO2, PuF6, and PuF4. We used a revised variant (PBEN) of the Perdew-Burke-Ernzerhof gradient-corrected exchange-correlation functional, and we accounted for spin-orbit interaction in a self-consistent fashion. As open-shell Pu species with two or more unpaired 5f electrons are involved, spin-orbit interaction significantly affects the energies of the model reactions. Our theoretical estimate for the heat of formation DeltafH degree 0(PuO2(2+),g), 418+/-15 kcal mol-1, evaluated using plutonium fluorides as references, is in good agreement with a recent experimental result, 413+/-16 kcal mol-1. The theoretical value connected to the experimental heat of formation of PuO2(g) has a notably higher uncertainty and therefore was not included in the final result.