Thermochromatographic Adsorption Studies of Curium and Berkelium

In preparation for thermochromatographic adsorption studies of Lr in metal columns at temperatures up to 2000 K we investigated the metal adsorption of Cm and Bk. Cm was chosen to model Lr as a trivalent metal and Bk as a trivalent actinide having a (divalent) fn+1s2 ground state configuration. 250Bk electroplated on tantalum and 248Bk/246Cm implanted in zirconium foils were used as actinide sources. To carry out an adsorption experiment the actinide sources were placed at the starting position of the thermochromatographic columns and hold for 30 min at 1850 K. Standard enthalpies of adsorption were calculated from the experimental results and compared with calculations using a semi-empirical method. Based on these results, the capability of the method for studying electronic and metallic state properties of the heaviest actinides up to Lr is discussed.