Search results for "ELECTRONIC STRUCTURE"
showing 10 items of 722 documents
Wannier90 as a community code: new features and applications
2019
Wannier90 is an open-source computer program for calculating maximally-localised Wannier functions (MLWFs) from a set of Bloch states. It is interfaced to many widely used electronic-structure codes thanks to its independence from the basis sets representing these Bloch states. In the past few years the development of Wannier90 has transitioned to a community-driven model; this has resulted in a number of new developments that have been recently released in Wannier90 v3.0. In this article we describe these new functionalities, that include the implementation of new features for wannierisation and disentanglement (symmetry-adapted Wannier functions, selectively-localised Wannier functions, s…
Self-assembly of Organic Molecules on Insulating Surfaces
2015
Molecular self-assembly is known to provide a powerful tool for creating functional structures, with the ultimate structure and functionality encoded in the molecular building blocks. Upon molecule deposition onto surfaces, functional structures have been created ranging from defect-free, highly symmetric two-dimensional layers to complex assemblies with dedicated functionality. Especially organic molecules play a key role for molecular self-assembly due to their impressive structural flexibility and the high degree of control by chemical synthesis. Furthermore, the surface itself provides another exciting dimension: adjusting the subtle balance between intermolecular and molecule-surface i…
Rational Design of Lanthanoid Single-Ion Magnets: Predictive Power of the Theoretical Models
2016
We report two new single‐ion magnets (SIMs) of a family of oxydiacetate lanthanide complexes with D3 symmetry to test the predictive capabilities of complete active space ab initio methods (CASSCF and CASPT2) and the semiempirical radial effective charge (REC) model. Comparison of the theoretical predictions of the energy levels, wave functions and magnetic properties with detailed spectroscopic and magnetic characterisation is used to critically discuss the limitations of these theoretical approaches. The need for spectroscopic information for a reliable description of the properties of lanthanide SIMs is emphasised. SPINMOL ERC-CoG-647301 DECRESIM MAT2014-56143-R CTQ2014-52758-P CTQ2011-2…
Exploring the High-Temperature Frontier in Molecular Nanomagnets: From Lanthanides to Actinides.
2019
Molecular nanomagnets based on mononuclear metal complexes, also known as single-ion magnets (SIMs), are crossing challenging boundaries in molecular magnetism. From an experimental point of view, this class of magnetic molecules has expanded from lanthanoid complexes to both d-transition metal and actinoid complexes. From a theoretical point of view, more and more improved models have been developed, and we are now able not only to calculate the electronic structure of these systems on the basis of their molecular structures but also to unveil the role of vibrations in the magnetic relaxation processes, at least for lanthanoid and d-transition metal SIMs. This knowledge has allowed us to o…
Electronic, Structural and Functional Versatility in Tetrathiafulvalene-Lanthanide Metal-Organic Frameworks
2019
<div>Tetrathiafulvalene-Lanthanide (TTF-Ln) Metal-Organic Frameworks (MOFs) are an interesting class of multifunctional materials in which porosity can be combined with electronic properties such as electrical conductivity, redox activity, luminescence and magnetism. Herein we report a new family of isostructural TTF-Ln MOFs, denoted as <b>MUV-5(Ln)</b> (Ln = Gd, Tb, Dy, Ho, Er), exhibiting semiconducting properties as a consequence of the short intermolecular S···S contacts established along the chain direction between partially oxidised TTF moieties. In addition, this family shows photoluminescence properties and single-molecule magnetic behaviour, finding near-infrared …
Anomalous Muon Knight Shift Behavior in a Cd Single Crystal
1983
For the positive muon implanted in a metal the precession frequency shift due to hyperfine fields can be measured with high precision. This provides means to obtain information about the local electronic structure of a hydrogen like impurity in any metal in the indefinitely dilute impurity concentration. Ref. 1 gives a summary of the muon Knight shift (KS) investigations in 18 nontransition (simple) metals and some transition metals and discusses the results in the context of the electronic structure of hydrogen in metals.
Dimeric Mn(ii), Co(ii), Ni(ii) and Cu(ii) complexes of a common carboxylate-appended (2-pyridyl)alkylamine ligand: structure, magnetism and DFT study
2021
Four new complexes of composition [MII2(L3)2(CH3OH)2](ClO4)2 (M = Mn, 1; Co, 2; Ni, 3) and [CuII2(L3)2](ClO4)2 (4) (L3(−) = 3-[2-(((6-methyl)pyridin-2-yl)methyl){(dimethylamino)ethyl}-amino]propionate) have been synthesized and characterized. Structural analysis reveals that 1–4 are discrete syn–anti carboxylate-bridged binuclear coordination complexes with a {MII2(–O–C–O–)2}2+ structural motif. In 1–3 distorted octahedral MN3O3 and in 4 distorted square pyramidal CuN3O2 coordination is satisfied at each M(II) center by three N (a pyridyl and two tertiary aliphatic amines) and a carboxylate O of the ligand, and an O of the carboxylate group. In 1–3 the M(II) center is also coordinated by a …
Influence of the Nature of the Ligand on Dirhodium(II) Carbene Species: A Theoretical Analysis
2008
The influence of three prototypic families of bridging ligands (carboxylate, carboxamidate, and ortho-metalated arylphosphines) on the electronic structure of dirhodium(II) carbene complexes was theoretically analyzed. The calculations indicated that the electron donation of the ligand to the Rh atom, rather than the chelating ability or the metal−ligand orbital mixing, was responsible for tuning carbene charge via back-donation, which can influence the reactivity and selectivity of the dirhodium complexes in catalytic carbene transfer reactions.
Electronic-structure-induced deformations of liquid metal clusters
1995
Ab initio molecular dynamics is used to study deformations of sodium clusters at temperatures $500\cdots 1100$ K. Open-shell Na$_{14}$ cluster has two shape isomers, prolate and oblate, in the liquid state. The deformation is stabilized by opening a gap at the Fermi level. The closed-shell Na$_8$ remains magic also at the liquid state.
Resistance simulations for junctions of SW and MW carbon nanotubes with various metal substrates
2011
Abstract This theoretical study focuses on junctions between the carbon nanotubes (CNTs) and contacting metallic elements of a nanocircuit. Numerical simulations on the conductance and resistance of these contacts have been performed using the multiple scattering theory and the effective media cluster approach. Two models for CNT-metal contacts have been considered in this paper: a) first principles “liquid metal” model and b) semi-empirical model of “effective bonds” based on Landauer notions on ballistic conductivity. Within the latter, which is a more adequate description of chirality effects, we have simulated both single-wall (SW) and multi-wall (MW) CNTs with different morphology. Res…