Structure and spectroscopy of actinide ion impurities in crystals

In this Section, we will show the results of sfss CGWB-AIMP embedded cluster calculations on the structure and spectroscopy of several actinide ions in chloride hosts. Altogether, they are aimed at showing the potentialities of present days wavefunction-based ab initio methods of Quantum Chemistry in materials made of heavy element ions in solids, with several open-shell electrons and a very large number of excited states of interest. 

As a second case, we study the 5/ and 5f 6d manifolds of l/ -doped Cs2ZrCl6, with two open-shell electrons [58]. Now, the manifolds contain a large number of electronic states and the general problems that will be faced all over the actinide series appear here. In particular, MS-CASPT2 methods will be used for dynamic correlation instead of demanding variational Cl based methods such as ACPF [82,83]. The calculations suggest several reassignments of the 5f- 5f experimental spectrum [84,85], predict the 5f 6d levels, and support the 

Finally, we study the 5f 6d manifold of U -doped Cs2NaYCl6 [59]. These calculations lead to interpretation of the experimental 5f- 6d absorption spectrum, which has been recorded but remained unassigned [88]. 

In the (PaCle) cluster, we have used Ae relativistic CGWB-AIMPs of the [Xe,4A5aT core of Pa 5f 6d 7s - and of the [Ne] core of Cl. We have used a 7s7py 3s4p standard valence basis set for Cl [8,33,93]. For Pa, however, we 

Calculated spectroscopic constants of the Sf and 6d manifolds of Cs2ZrCl6 (PaCl6) corresponding to the CGWB-AIMP spin-orbit embedded cluster Hamiltonian. Available experimental data are shown in parentheses.  

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