Be-Be π bonding and predicted superconductivity in MBe2 (M=Zr, Hf)

The Amsterdam Modeling Suite

In this paper, we present the Amsterdam Modeling Suite (AMS), a comprehensive software platform designed to support advanced molecular and materials simulations across a wide range of chemical and physical systems. AMS integrates cutting-edge quantum chemical methods, including Density Functional Theory (DFT) and time-dependent DFT, with molecular mechanics, fluid thermodynamics, machine learning techniques, and more, to enable multi-scale modeling of complex chemical systems. Its design philosophy allows for seamless coupling between components, facilitating simulations that range from small molecules to complex biomolecular and solid-state systems, making it a versatile tool for tackling interdisciplinary challenges, both in industry and in academia. The suite also emphasizes user accessibility, with an intuitive graphical interface, extensive scripting capabilities, and compatibility with high-performance computing environments.

Identification of Global Minimum of HNBeCO Complex

Multiple bonding has always excited chemists. Recently, triple bonding between beryllium and N atoms in the HNBeCO complex has been reported based on experimental infrared spectroscopy and theoretical calculations. However, the present work reports a different structure based on a detailed potential energy surface scan. The global minimum geometry features only a weak partial Be-N double bond. The global minimum geometry lies very deep in the potential energy surface with respect to the reported one. Isomerization kinetics reveals that the reported structure has to overcome a very small barrier (5.4 kcal/mol) to isomerize to the global one. Although the previously reported structure is a real minimum, the present study identifies a much lower energy structure. A re-examination of the experimental spectra might show that the global minimum has also been observed.

Thickness-Dependent Superconductivity in a Layered Electride on Silicon

Layered materials exhibit a plethora of fascinating properties. The challenge is to make the materials into epitaxial films, preferably integrated with mature technological platforms to facilitate their potential applications. Progress in this direction can establish the film thickness as a valuable parameter to control various phenomena, superconductivity in particular. Here, a synthetic route to epitaxial films of SrAlSi, a layered superconducting electride, on silicon is designed. A set of films ranging in thickness is synthesized employing a silicene-based template. Their structure and superconductivity are explored by a combination of techniques. Two regimes of TC dependence on the film thickness are identified, the coherence length being the crossover parameter. The results can be extended to syntheses of other honeycomb-lattice ternary compounds on Si or Ge exhibiting superconducting, magnetic, and other properties.

Versatile transition metal monolayers with catalytic and superconducting properties: a computational study

Due to their abundant valence electrons and unique electronic properties, transition metals have garnered great interest in the search for novel materials displaying various properties, including superconductivity, catalysis and so on. XRu₂ (X: V, Mn, Fe, etc.) compounds, which are isostructural to AlB₂, were used as examples for which we performed extensive simulations to screen for superconductivity and possible potential catalytic activity. On this basis, we found that VRu₂ could achieve a superconducting critical temperature (T_c) of about 13 K. Meanwhile, our simulations showed the lowest adsorption free energy of atomic hydrogen (ΔG_H) on the (0 0 1) surface of VRu₂ to be about 2 meV, indicating its almost zero free energy of hydrogen adsorption with excellent catalytic performance. In addition, the results suggested potential superconducting and catalytic properties of VXRu (X = Os, Fe). Our current results have shed light on possible applications of Ru-based AlB₂-type intermetallic compounds and have presented a new strategy for further designing superconductors and catalysts based on transition metals.

Triple bonding between beryllium and nitrogen in HNBeCO

The HNBeCO complex is generated via the reaction of a beryllium atom with a HNCO molecule in a solid neon matrix, which is identified via infrared absorption spectroscopy with isotopic substitutions. The complex is characterized to have a linear structure with a very short Be-N bond distance. Bonding analyses indicate that the complex involves an unprecedented HNBeCO triple bond consisting of two degenerate electron-sharing π bonds and a dative σ bond with the π bonds being much stronger than the σ bond.