Studies of Selected Transuranium and Lanthanide Triiodides under Pressure Using Absorption Spectrophotometry

摘要

The anhydrous triiodides of plutonium, americium, and curium under pressure have been investigated using absorption spectrophotometry. These initial studies on plutonium and curium triiodides together with the published data for americium triiodide show that the rhombohedral (BiI sub 3 -type structure) form of these compounds can be converted to the same orthorhombic (PuBr sub 3 -type structure) form by applying pressure at room temperature. Absorption spectrophotometry can often differentiate between two crystallographic forms of materials and has been used in the present high pressure studies to monitor the effects of pressure on the triiodides. A complication in these studies of the triiodides is a significant shift of their absorption edges from the near uv to the visible spectral region with pressure. With curium triiodide this shift causes interference with the major f-f absorption peaks and precludes identification by absorption spectrophotometry of the high pressure phase of CmI sub 3 . 21 refs., 2 figs. (ERA citation 12:020724)