Transuranium materials under extreme pressures
The diamond anvil technique and its potential are briefly introduced. A few results of high-pressure studies of transuranium metals and their compounds are described. These include the delocalisation of 5f electrons in the heavy actinide metals Am, Cm, Bk and Cf, and structural phase transitions in alpha-plutonium under pressure by HPXRD. A general diagram of the phase relations of actinides under pressure is illustrated. It highlights trends in structures and phase transitions, and indicates where further research is needed. Increasing pressure and decreasing atomic number lead to transformation of high-symmetry structures into structures of lower symmetry. The study of actinide compounds of the B1 structure type by X-ray diffraction, X-ray absorption and optical reflectivity is presented. Compounds with heavy anions Se, Te, As and Sb generally transform to the B2 structure under pressure and are accompanied by changes in optical reflectivity. Phase transitions in UC and UP to less symmetric high-pressure structures are accompanied by a shift of the LIII X-ray absorption edge. Other studies include compression of PuAs up to 45 GPa and comparison with ThAs, UAs and NpAs.
Bibliographic Reference: Paper presented: Transuranium Elements Today and Tomorrow, Karlsruhe (DE), Oct. 26-27, 1988 Article: Journal of Nuclear Materials, Np. 166 (1989), pp. 48-55
Availability: Available from (1) as Paper EN 34556 ORA
Record Number: 198911066 / Last updated on: 1994-12-01
Original language: en
Available languages: en