The ground-state molecular properties of the trichlorides of light actinides (An = Th–Cm) have been predicted by state-of-the-art quantum chemical calculations. The ground electronic states have been determined by multireference calculations at the CASPT2 level including both scalar and spin-orbit relativistic effects. These studies supported the expected single-configuration character of ThCl3 and CmCl3 with their well-defined 6d0/7s hybrid and 5f7 configurations, respectively. In contrast, the intermediate actinides (PaCl3 – AmCl3) with partly filled 5f shells have numerous very low-lying excited states and consequently a mixed character of the spin-orbit ground states. Apart from the planar ThCl3 the ground-state molecular geometries proved to be pyramidal with C3v symmetry. The gradually decreasing An-Cl bond distances reveal the actinide contraction known for the atomic and ionic radii of these actinide atoms. Other ground-state molecular properties as vibrational frequencies and natural charges have been obtained by Density Functional Theory calculations using the B3LYP exchange-correlation functional in conjunction with small-core relativistic energy-consistent pseudopotentials for the actinides.

KOVACS Attila;  KONINGS Rudy;  VARGA Zoltán;  SZIEBERTH Dénes; 

2013-12-03

AMER CHEMICAL SOC

JRC83790

1089-5639,   

http://pubs.acs.org/doi/abs/10.1021/jp407855j,    https://publications.jrc.ec.europa.eu/repository/handle/JRC83790,   

10.1021/jp407855j,