Effect of the f-Orbital Delocalization on the Ligand-Field Splitting Energies in Lanthanide-Containing Elpasolites

Abstract

Abstract:The ligand-field induced splitting energies of f-levels in lanthanide-containing elpasolites are derived using the first-principles universal orbital-free embedding formalism [Wesolowski and Warshel, J. Phys. Chem. 1993, 97, 8050]. In our previous work concerning chloroelpasolite lattice (Cs 2 NaLnCl 6 ), embedded orbitals and their energies were obtained using an additional assumption concerning the localization of embedded orbitals on preselected atoms leading to rather good ligand-field parameters. In this work, the validity of the localization assumption is examined by lifting it. In variational calculations, each component of the total electron density (this of the cation and that of the ligands) spreads over the whole system. It is found that the corresponding electron densities remain localized around the cation and the ligands, respectively. The calculated splitting energies of f-orbitals in chloroelpasolites are not affected noticeably in the whole lanthanide series. The same computational procedure is used also for other elpasolite lattices (Cs 2 NaLnX 6 , where X)F, Br, and I)smaterials which have not been fabricated or for which the ligand-field splitting parameters are not available.

Chromophore-specific theoretical spectroscopy: From subsystem density functional theory to mode-specific vibrational spectroscopy

“…In these types of applications, FDE can partly cure the problem of too large covalent contributions or too large mixing between f orbitals of the cation and ligand orbitals present in conventional DFT calculations. This particular point was the subject of another recent study, in which the restriction to localized embedded orbitals was lifted [191].…”

“…and F-H-F − , and subsystems connected by coordination bonds have been investigated in that work. Even though there are a few applications of FDE to such systems, e.g., for MnF 4− 6 [190], lanthanide complexes [189,191], or zinc complexes [188], subsystems connected by donor-acceptor bonds represent a big challenge and push the currently available approximations for the non-additive kinetic energy to their limits.…”

A non-empirical calculation of 2p core-electron excitation in compounds with 3d transition metal ions using ligand-field and density functional theory (LFDFT)

“…Fig. 3 Table 2, with respect to Russel-Saunders coupling and spin-orbit coupling schemes together with the dimension of the effective ligand-field Hamiltonian calculated by means of eqn (7) and (8). The intensity calculations are obtained within the electric-dipolar approximation.…”

Molecular properties via a subsystem density functional theory formulation: A common framework for electronic embedding

“…33 His formulation does not only recover important environment contributions 34 on polarizabilities and excitation energies in dimers, but also allows for the coupling of local excitations in a complete model. 35 A growing number of applications shows the promise of subsystem DFT in both the (frozen-density) embedding mode [36][37][38][39][40] as well as in the (fully self-consistent) subsystem mode 41 to describe molecular properties.…”