Metal coordination study at Ag and Cd sites in crown thioether complexes through DFT calculations and hyperfine parameters

Abstract

Structural and electronic properties of [C12H24S6X], [C13H26S6OX], and [C14H28S6OX] (X: Ag(+), Cd(2+)) crown thioether complexes were investigated within the framework of the density functional theory (DFT) using the projector augmented wave (PAW) method. The theoretical results were compared with time-differential perturbed γ-γ angular correlations (TDPAC) experiments reported in the literature using the (111)Ag→(111)Cd probe. In the case of X=Ag(+), a refinement of the structure was performed and the predicted equilibrium structures compared with available X-ray diffraction experimental data. Structural distortions induced by replacing Ag(+) with Cd(2+) were investigated as well as the electric-field gradient (EFG) tensor at the Cd(2+) sites. Our results suggest that the EFG at Cd(2+) sites corresponds to the Ag(+) coordination sphere structure, i.e., before the structural relaxations of the molecule with X=Cd(2+) are completed. The results are discussed in terms of the characteristics of the TDPAC (111)Ag→(111)Cd probe and the time window of the measurement, and provide an interesting tool with which to probe molecular relaxations.

Electric field gradient study on pure and Cd-doped In(111) surfaces: Correlation between experiments at the atomic scale and first-principles calculations

“…Nowadays, confronting precise experimental determinations of the EFG tensor with very accurate theoretical predictions [9,14,[18][19][20][21][22][23][24][25][26], using all-electron state-of-the-art ab initio electronic structure calculations in the framework of the density functional theory (DFT) [27,28], it is possible to obtain valuable information about structural lattice deformations, localization and charge state of impurities and defect centers, impurity energy levels, and structural and magnetic phase transitions, among other interesting properties. The correlation between the EFG and the electronic charge density ρ( r) in a physical system is so strong that the agreement between the experimental and predicted EFG validates the ρ( r) description and hence all the ground-state properties.…”

Experimental TDPAC and Theoretical DFT Study of Structural, Electronic, and Hyperfine Properties in (111In → )111Cd-Doped SnO2 Semiconductor: Ab Initio Modeling of the Electron-Capture-Decay After-Effects Phenomenon

“…In the last years, in condensed-matter physics, structural, electronic, and magnetic properties in pure and doped systems have been carefully studied at the atomic scale confronting results from hyperfine experimental techniques with reliable all-electron (AE) ab initio predictions in the framework of the density functional theory (DFT). − In particular, the subnanoscopic environment of impurities or native atoms in solids can be studied employing the time-differential perturbed γ–γ angular-correlation (TDPAC) spectroscopy. This technique provides a very precise characterization of the electric-field-gradient (EFG) tensor at diluted (ppm) radioactive probe atoms.…”