Search results for "Density"
showing 10 items of 4402 documents
The Role of the Anchor Atom in the Ligand of the Monolayer-Protected Au25(XR)18– Nanocluster
2015
We present a density functional theory (DFT) investigation on the role of the anchor atom and ligand on the structural, electronic, and optical properties of the anionic Au25(XR)18– nanocluster (X = S, Se, Te; R = H, CH3, and (CH2)2Ph). Substituting the anchor atom with other group 16 elements induces subtle changes in the Au–Au and Au–X bond lengths and polarization of the covalent bond. The changes in the electronic structure based on substituting both the anchor and R groups are presented through careful analysis of the density of states and theoretical determined optical spectra. We give a detailed side-by-side comparison into the structural, electronic, and optical properties of Au25(X…
The electronic structure of Ge9[Si(SiMe3)3]3-: a superantiatom complex.
2012
We report on the electronic structure of Ge(9)[Si(SiMe(3))(3)](3)(-). Systematic density functional theory analysis of the electronic shell structure of the cluster and its derivatives reveals that the Ge(9)[Si(SiMe(3))(3)](3)(-) and its neutral counterpart have electronic shells that can be explained using the superatom model. The ligand-core interaction of these complexes is distinctly different from previously identified gold, gallium, and aluminium superatom complexes, indicating an electron-donating rather than electron-withdrawing ligand. We modify the electron-counting rule for this case and introduce a simple picture for superatom and superantiatom complexes. Discussions comparing s…
Crystal Structures and Density Functional Theory Calculations of o-and p-Nitroaniline Derivatives: Combined Effect of Hydrogen Bonding and aromatic i…
2013
The interplay of strong and weak hydrogen bonds, dipole–dipole interactions, and aromatic interactions of o- and p-nitroaniline derivatives was studied by combining crystal structure analysis and density functional theory (DFT) calculations. Crystal structures of four 2-nitroaniline derivatives, 2-((2-nitrophenyl)amino)ethyl methanesulfonate (1A), 2-((2-nitrophenyl)amino)ethyl 4-methylbenzenesulfonate (2A), N,N′-((1,3-phenylenebis(oxy))bis(ethane-2,1-diyl))bis(2-nitroaniline) (3A), and N-(2-chloroethyl)-2-nitroaniline (4A), and crystal structures of three 4-nitroaniline derivatives, 2-((4-nitrophenyl)amino)ethyl methanesulfonate (1B), 2-((4-nitrophenyl)amino)ethyl 4-methylbenzenesulfonate (…
Evaluation of alveolar cortical bone thickness and density for orthodontic mini-implant placement.
2013
Objective: Mini-implant stability is primarily related to bone quality and quantity. This study evaluated alveolar cortical bone thickness and density differences between interradicular sites at different levels from the alveolar crest, and assessed the differences between adolescents (12-18 years of age) and adults (19-50 years of age), males and females, upper and lower arch, anterior and posterior region of jaws and buccal and oral side. Study Design: In this retrospective study, 48 Computed Tomography scans, performed for oral surgery purposes were selected from dental records of 3,223 Caucasian orthodontic patients. The SimPlant software (Materialise, Leuven, Belgium) was used to measu…
Understanding the White-Emitting CaMoO4 Co-Doped Eu3+, Tb3+, and Tm3+ Phosphor through Experiment and Computation
2019
In this article, the synthesis by means of the spray pyrolysis method, of the CaMoO4 and rare-earth cation (RE3+)-doped CaMoO4:xRE3+ (RE3+ = Eu3+, Tb3+, and Tm3+; and x = 1, 2, and 4% mol) compounds, is presented. The as-synthesized samples were characterized using X-ray diffraction, Rietveld refinement, field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) spectroscopy. To complement and rationalize the experimental results, first-principles calculations, at the density functional theory level, have been performed to analyze the band structure and density of states. In addition, a theoretical method based on the calculations of surface energie…
Tunable Interaction Strength and Nature of the S···Br Halogen Bonds in [(Thione)Br2] Systems
2015
The strength and nature of the S···Br and Br···Br interactions were systematically tuned by altering the electron donor properties of the thione group. Three new halogen-bonded compounds, [(N-methylbenzothiazole-2-thione)Br2]·0.5CH2Cl2 (1), [(2(3H)-benzothiazolethione)Br2] (2), and [(2-benzimidazolethione)Br]·[Br3] (3), were synthesized and studied structurally by using X-ray crystallography and computationally by using charge density analysis based on QTAIM calculations. Analysis of the interaction strength indicated a formation of surprisingly strong S···Br halogen bonds in 1 (−104 kJ mol–1, and RBrS = 0.64) and 2 (−116 kJ mol–1, and RBrS = 0.63) with a substantial covalent contribution. …
Dirakův kužel a pseudogapped hustota stavů v topologické polovině Heuslerovy sloučeniny YPtBi
2016
Topologické izolátory (Tis) jsou zajímavé materiály, které vykazují nebývalé vlastnosti. . Zde jsme prozkoumali sloučeniny YPtBi jako příklad ze třídy polovu-Heuslerových materiálů. Topological insulators (TIs) are exciting materials, which exhibit unprecedented properties, such as helical spinmomentum locking, which leads to large torques for magnetic switching and highly efficient spin current detection. Here we explore the compound YPtBi, an example from the class of half-Heusler materials, for which the typical band inversion of topological insulators was predicted. We prepared this material as thin films by conventional cosputtering from elementary targets. By in situ time-of-flight mo…
Recommendations of the LHC Dark Matter Working Group: Comparing LHC searches for dark matter mediators in visible and invisible decay channels and ca…
2019
Physics of the Dark Universe 26, 100377 (2019). doi:10.1016/j.dark.2019.100377
Using machine learning on tree-ring data to determine the geographical provenance of historical construction timbers
2023
Funder: Bavarian Climate Research Network (BayKliF)
Exploring the Relationship Between Trust and Business Start-Ups in 52 Countries Over 16 Years
2021
A well-functioning social network involves attributes such as honesty, benevolence, fairness and confidence. When this network – trust - has formed, participants can count on reliable and consistent economic transactions. This has the effect of higher level of co-operation, but also co-dependence. Strong social networks, as measured in this study by the degree of interpersonal trust and trust in institutions, are foundational elements for societies wishing to progress to new higher levels of entrepreneurship and development. In a pooled OLS of up to 52 countries and 16 years, this study estimates how changes in interpersonal trust and trust in institutions affect new business creation. The …