Yi Luo

A density functional theory calculation on lanthanide monosulfides

Abstract Density functional calculations have been performed on several lanthanide monosulfide molecules, LnS (Ln=La, Ce, Eu, Gd, Yb and Lu). In agreement with experimental data, our theoretical results suggest that some estimated data for LnS molecules should be revised. Compared with 5d 1 4f n ( n =0,1,7,14) configurations of free Ln atom, 5d 0 4f m ( m =7,14) configurations resulted in lower dissociation energy and vibration frequency, as well as larger hardness of LnS molecules. The calculated lanthanide contraction of 0.1 A for LnS molecules is consistent with the rigidity of Ln–S bond. With the effect of 5d 0 and 5d 1 configurations, the binding behaviors of Ln-4f orbital were discussed in LnS molecules.

Density functional study of lanthanide complexes (η5-C5H5)2LnX·OC4H8 (Ln=La–Lu; X=F, Cl, Br and I)

Abstract Density functional calculations were performed on a series of mixed-ligand organolanthanide complexes, (η 5 -C 5 H 5 ) 2 LnX·OC 4 H 8 (η 5 -C 5 H 5 =Cp; Ln=La–Lu; X=F, Cl, Br and I; OC 4 H 8 =THF). The calculated geometrical parameters are in reasonable agreement with the experimental data. The distances between Ln and ligands follow linearity along the ionic radius of lanthanide metal, as the same as that observed in experiment. In the mixed-ligand complexes, Ln–Cp and Ln–THF bonds are more covalent compared to Ln–X. The lanthanide contraction of various bond and the metal–ligand interaction energy followed the order of Ln–X>Ln–Cp>Ln–OC 4 H 8 . The orbital population and dipole moment were also discussed.

Theoretical investigation of mixed-ligand lanthanocene complexes, (η5-C5H5)2LnX · OC4H8 (Ln=La, Gd, Lu; X=F, Cl, Br, I)

Abstract For the first time, density functional theory (DFT) calculation was performed on the titled complexes and the calculated geometries are in good agreement with the available experimental data. The decrease in the bond distances (Ln–X) as well as the increase in the Hirshfeld charges and the chemical hardness from La to Lu indicates an increase in ionic character on going from La to Lu. The lanthanide contraction and ionic character of metal–ligand bond are found to follow the order: Ln–Xxa0>xa0Ln–Cpxa0>xa0Ln–O.

The adsorption of nitrogen oxides and water on rare-earth ion-exchanged ZSM-5: a density functional study

Abstract In this study, we present the adsorption behavior of NO, NO2 and H2O on trivalent rare-earth ion-exchanged ZSM-5 (RE-ZSM-5; RE=La, Ce, Nd, Sm, Gd and Dy) using density functional theory. The results show that Ce-ZSM-5 is more effective for the activation of NOx than La-ZSM-5 and Nd-ZSM-5, which is in good agreement with experimental results. The present investigation also suggests that Dy-ZSM-5 has a considerable ability for the activation of NO2 as compared to Sm-ZSM-5 and Gd-ZSM-5. Furthermore, the Ce-, Nd- and Dy-analogues posses a quite stronger affinity for NOx and that the low affinity of H2O indicate the poisoning resistance ability of these catalysts. In addition, the relationship between the adsorption energy of NO and the contribution of NO-2πg1 molecular orbital was also investigated in the NO/RE-ZSM-5 adsorption complex.

19.3: Electronic Structure Calculation and QSPR Analysis of Eu2+‐doped Oxide Phosphors: Relationship between Emission Wavelength and Crystal Structure

In this study, we have computationally revealed the relationship between crystal structure and emission wavelength for Eu2+-doped oxide phosphors. The quantum chemistry calculations and quantitative analysis of structure-property relationship suggested that both O and alkaline-earth (A) atoms around the Eu atom in phosphors are of importance for emission wavelength. This extension of the consideration range for interaction of A atoms gave the simple guideline for the emission wavelength control of Eu2+-doped phosphors: 1) The host materials which have many A atoms and shorter/longer A-A/A-O distances are suitable to get longer Eu2+ emission wavelength, 2) The host materials which have less A atoms and longer/shorter A-A/A-O distances are suitable to get shorter Eu2+ emission wavelength.