Topology of the Electron Density and of Its Laplacian from Periodic LCAO Calculations on f-Electron Materials: The Case of Cesium Uranyl Chloride

Abstract

The chemistry of f-electrons in lanthanide and actinide materials is yet to be fully rationalized. Quantum-mechanical simulations can provide useful complementary insight to that obtained from experiments. The quantum theory of atoms in molecules and crystals (QTAIMAC), through thorough topological analysis of the electron density (often complemented by that of its Laplacian) constitutes a general and robust theoretical framework to analyze chemical bonding features from a computed wave function. Here, we present the extension of the Topond module (previously limited to work in terms of s-, p- and d-type basis functions only) of the Crystal program to f- and g-type basis functions within the linear combination of atomic orbitals (LCAO) approach. This allows for an effective QTAIMAC analysis of chemical bonding of lanthanide and actinide materials. The new implemented algorithms are applied to the analysis of the spatial distribution of the electron density and its Laplacian of the cesium uranyl chloride, Cs2UO2Cl4, crystal. Discrepancies between the present theoretical description of chemical bonding and that obtained from a previously reconstructed electron density by experimental X-ray diffraction are illustrated and discussed.

CRYSTAL23: A Program for Computational Solid State Physics and Chemistry

“…This resulted in an highly efficient algorithm, which, however, may not be easily generalized to higher quantum numbers. A new algorithm has therefore been devised (general to s -, p -, d -, f -, and g -type orbitals) by a direct evaluation of the AO overlap distribution (and its first to fourth derivatives) in the RSSH-GTF basis. , This new algorithm, being less efficient than the previous one based on an expansion in Hermite GTFs, is only activated upon runtime if f - and g -type orbitals are used in the basis set for a particular calculation.…”

“…This opens the possibility for a topological analysis of the electron density of lanthanide and actinide containing systems, with f electrons in the valence. 183,184 The previous strategy (general to s-, p-, and d-type RSSH-GTFs) was based on an expansion of the AO overlap distribution in eq 35a into Hermite GTFs, using eqs 55, 56, 58, and 60. This resulted in an highly efficient algorithm, which, however, may not be easily generalized to higher quantum numbers.…”

Insight into the inclusion of heteroatom impurities in Silicon structures

“…A great variety of bonding situations can be explained and therefore interpreted in relation to physical properties. [21][22][23][24][25][26][27][28] In this work, we highlight on chemical bonding of the C, N and O local structures in Silicon bulk and in Silicon GB Σ3{111} with and without vacancies. In order to understand the organization and the underlying electronic structure of the inclusion of C, O and N atoms in Si structures, we focus on topological analysis obtained from density distribution.…”

Insight into the inclusion of heteroatom impurities in silicon structures

“…A great variety of bonding situations can be explained and therefore interpreted in relation to physical properties. [21][22][23][24][25][26][27][28] In this work, we highlight chemical bonding of the C, N and O local structures in silicon bulk and in silicon GB S3{111} with and without vacancies. In order to understand the organization and the underlying electronic structure of the inclusion of C, O and N atoms in Si structures, we focus on topological analysis obtained from density distribution.…”

“…A great variety of bonding situations can be explained and therefore interpreted in relation to physical properties. 21–28…”