AB-INITIO QUANTUM-CHEMICAL CALCULATIONS ON URANYL UO22+ PLUTONYL PUO22+, AND THEIR NITRATES AND SULFATES

Ab initio molecular orbital calculations on the structure and stabilit y of the nitrate and sulfate and sulfate complexes of uranyl (UO22+) a nd plutonyl (PuO22+) using effective core potentials are reported. It is found that the binding energy of sulfate is greater than that of ni trate to both uranyl and plutonyl, with a slight preference for pluton yl. A method of decomposing the binding energy into electrostatic, Pau li repulsion, polarization and charge-transfer components is described which predicts that electrostatic forces are dominant. A simple molec ular mechanics potential is developed by using this finding, which is successful in reproducing the ab initio results.