In order to gain advanced understanding of the kinetics and dynamics of C, N, and O reacting with a solid surface, it is necessary to consider the reaction from the perspectives of bond formation, bond dissociation, bond relaxation, bond vibration, and the associated charge redistribution and polarization and the energetic response of the involved atoms and valence electrons. The sp-orbital hybridization is found necessary for these concerned reactions associated with strongly anisotropic bonding and valence identities and the localized energy states of bonding pairs, nonbonding lone pairs, and the lone pair induced antibonding dipoles, as well as the hydrogen bond like and C-H bond like states, which could unify the observations using atomistic microscopy, crystallography, electronic spectroscopy, vibronic spectroscopy, and thermal desorption spectroscopy and provide guidelines for materials design.
Tetrahedrite-based ($\textrm{Cu}_{12}\textrm{Sb}_{4}\textrm{S}_{13}$) materials are candidates for good thermoelectric generators due to their intrinsic, very low thermal conductivity and high power factor. One of the current limitations is virtual absence of tetrahedrites exhibiting n--type conductivity. In this work, first-principles calculations are carried out to study Mg-doped tetrahedrite, $\textrm{Mg}_{x}\textrm{Cu}_{12}\textrm{Sb}_{4}\textrm{S}_{13}$ with possibility of predicting n--type material in mind. Different concentrations and modifications of the structure are investigated for…
The chemical bond is one of the most powerful, yet controversial concepts in chemistry, explaining property trends in solids. Recently, a novel type of chemical bonding has been identified in several higher chalcogenides, characterized by a unique property portfolio, unconventional bond breaking and sharing of about one electron between adjacent atoms. Metavalent bonding is a fundamental type of bonding besides covalent, ionic and metallic bonding, raising the pertinent question, if there is a well-defined transition between metavalent and covalent bonding. For three different pseudo-binary li…
While solid-state materials are commonly classified as covalent, ionic, or metallic, there are cases that defy these iconic bonding mechanisms. A prominent example is given by phase-change materials (PCMs) for data storage or photonics, which have recently been argued to show 'resonant' bonding; a clear definition of this mechanism, however, has been lacking until the present day. Here we show that these solids are clearly different from resonant bonding in the pi-orbital systems of benzene and graphene. Instead, they exhibit a unique mechanism between covalent and metallic bonding, which we c…
Bonding between polymeric interfaces is encountered widely in several industrial applications. Many of these bonding processes rely on time-consuming and temperature-dependent classical mechanism of polymer interdiffusion via reptation in a melt state. Here, for the first time, we report a new mechanistic pathway for achieving solid-state polymer bonding by triggering rapid macromolecular acceleration through mechanical deformation. Large-scale molecular simulations reveal that active plastic deformation in glassy polymers, at temperatures well-below the bulk (and surface) glass transition tem…
Classification of Metal - Insulator Transitions: Relating characteristic Properties to Quantum Chemical Bonding Descriptors
RWTH Aachen University（亚琛工业大学）；John A. Paulson School of Engineering and Applied Sciences, Harvard University（哈佛大学约翰·A·保尔森工程与应用科学学院）；School of Advanced Materials JNCASR（JNCASR高级材料学院）；Forschungszentrum Jülich GmbH（于利希研究中心有限公司）
Bonding Signatures of Incipient Electron Localization in Topological Chiral Semimetals Near the Metal-Insulator Transition
RWTH Aachen University（亚琛工业大学）；Max Planck Institute for Chemical Physics of Solids（马克斯·普朗克固体物理研究所）；ESPCI Paris, Université PSL, CNRS, Sorbonne Université（巴黎高等物理化工大学、巴黎文理研究大学、法国国家科学研究中心、索邦大学）；Peter Grünberg Institute – JARA-Institute Energy Efficient Information Technology (PGI- 10)（彼得·格林贝格研究所 - JARA能源高效信息技术研究所）
The influence of spin-orbit interaction on chemical bonds in elemental solids and homonuclear dimers is analyzed by means of density-functional-theory calculations. Employing highly precise all-electron full-potential methodology, our results represent benchmark quality. Comparison of the scalar- and fully-relativistic approaches for elemental solids shows that the spin-orbit interaction may contract or expand the volume of the considered material. The largest variation of the volume is obtained for Au, Tl, I, Bi, Po and Hg, exhibiting changes between 1.0--7.6\%. Using the tight-binding model,…
The assembly of complex structures is driven by an interplay between several intermolecular interactions, from strong covalent bonds to weaker dispersion forces. Surface-based self-assembly is particularly amenable to modeling and measuring these interactions in well-defined systems. This study focuses on 2-butanol, the simplest aliphatic chiral alcohol. 2-butanol shows interesting properties as a chiral modifier of surface chemistry, however, its mode of action is not fully understood. In order to probe its surface properties we employed high-resolution scanning tunneling microscopy and DFT s…
Understanding the nature of chemical bonding in solids is crucial to comprehend the physical and chemical properties of a given compound. To explore changes in chemical bonding in lead chalcogenides (PbX, where X = Te, Se, S, O), a combination of property-, bond breaking- and quantum-mechanical bonding descriptors have been applied. The outcome of our explorations reveals an electron transfer driven transition from metavalent bonding in PbX (X = Te, Se, S) to iono-covalent bonding in beta-PbO. Metavalent bonding is characterized by adjacent atoms being held together by sharing about a single e…
Trends in structural, electronic properties, Fermi surface topology, and inter-atomic bonding in the series of ternary layered dichalcogenides KNi2S2, KNi2Se2, and KNi2Te2 from first principles calculations
利用FLAPW-GGA方法，我们系统地研究了四硫属二硫化物KNi_2CH_2（CH = S，Se，Te）的结构和电子性质.结果表明，硫族元素（S -> Se -> Te）的置换导致晶体结构的各向异性变形，这与[Ni_2Ch_2]块内原子间键的强各向异性有关，在[Ni_2Ch_2]块内形成共价-离子-金属混合键，而在相邻的[Ni_2Ch_2]块和K原子片之间形成离子键.我们发现在KNi_2S_2-> KNi_2Se_2-> KNi_2 Te_2的顺序中（i）整个能带结构（其中近费米价带主要由Ni态产生）的能级保持不变，但公共价带的宽度、分立子带和带隙的宽度减小;（iii）对于费米面，当类二维片形成项链状拓扑结构且封闭口袋的体积减小时，类孔片表现出最明显的变化.讨论了ThCr_2Si_2型层状二硫属化合物KNi_2Ch_2、KFe_2Ch_2、KCo_2Se_2的结构和电子参数的变化趋势。
Presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of multiferroic (1-x)Bi(Ni1/2Ti1/2)O3-xPbTiO3 solid solution: A Rietveld study
我们在这里提出的多铁性（1-x）Bi（Ni 1/2 Ti 1/2）O3-xPbTiO 3固溶体的结构研究的结果，使用Rietveld分析的粉末X射线衍射数据的组成范围为0.35至0.55。我们精确地测定了（1-x）Bi（Ni_（1/2）Ti_（1/2））O_（3-x）PbTiO_3在室温下的稳定区。通过划分准同型相界的相共存区，观察到了从准立方相到四元相的结构转变。准同型相界区由四斜晶系和单斜晶系共存的结构组成，空间群分别为P4 mm和Pm，Rietveld分析证实其组成范围为0.41 ~ 0.49。Rietveld分析的结果完全排除了早期工作者报道的在准同型相边界区菱面体相和四面体相共存的可能性。Rietveld精化后得到的B-位阳离子-氧阴离子的键长与使用Shannon-Prewitt离子半径计算的键长之间的比较，揭示了立方相的B-O键的离子性质和其他结晶相的部分共价特征。
The bonding properties of tilt boundary in poly-silicon and the effect of interstitial impurities are investigated by first-principles. In order to obtain thorough information on the nature of chemical bondings in these solid systems, an accurate topological analysis is performed, through partitioning of the electron localization function. Although the mechanism of segregation of single light impurities, such as carbon, nitrogen, and oxygen in Si-based systems is known, it is only in the presence of multiple segregations that the distinctive structures of the various interstitial impurities em…
The electronic structure and chemical bonding in reactively magnetron sputtered ZrHx (x=0.15, 0.30, 1.16) thin films with oxygen content as low as 0.2 at% are investigated by 4d valence band, shallow 4p core-level and 3d core-level X-ray photoelectron spectroscopy. With increasing hydrogen content, we observe significant reduction of the 4d valence states close to the Fermi level as a result of redistribution of intensity towards the H 1s - Zr 4d hybridization region at about 6 eV below the Fermi level. For low hydrogen content (x=0.15, 0.30), the films consist of a superposition of hexagonal …
Using Sohn's law of additive reaction times for modeling a multiparticle reactor. The case of the moving bed furnace converting uranium trioxide into tetrafluoride
Amorphous solid water (ASW) is abundantly present in the interstellar medium, where it forms a mantle on interstellar dust particles and it is the precursor for cometary ices. In space, ASW acts as substrate for interstellar surface chemistry leading to complex molecules and it is postulated to play a critical role in proton-transfer reactions. Although ASW is widely studied and is generally well characterized by different techniques, energetically-induced structural changes, such as ion, electron and photon irradiation, in these materials are less well understood. Selective pumping of specifi…
Many atomic liquids can form transient covalent bonds reminiscent of those in the corresponding solid states. These directional interactions dictate many important properties of the liquid state, necessitating a quantitative, atomic-scale understanding of bonding in these complex systems. A prototypical example is liquid silicon, wherein transient covalent bonds give rise to local tetrahedral order and consequent non-trivial effects on liquid state thermodynamics and dynamics. To further understand covalent bonding in liquid silicon, and similar liquids, we present an ab initio simulation-base…
