Journal of Computational Chemistry最新文献

The structural, electronic, and optical properties of 13-atom Au-Ag-Cu ternary clusters are systematically investigated using density functional theory (DFT). The results indicate that the structural configurations of Ag_11−nCu₂Au_n (n = 2, 3, 4, 5, 6, 7, 9), Ag_10−nCu₃Au_n (n = 3, 4, 6, 7, 8, 9), Ag_8−nCu₅Au_n (n = 4, 5, 6, 7), Ag_11−nCu₁Au_n (n = 8, 9), Ag_7−nCu₆Au_n (n = 5, 6), and Ag_6−nCu₇Au_n (n = 3, 5) clusters exhibit irregular structural configurations, while other ternary clusters exhibit icosahedral-like geometries. In terms of stability, Ag₉Cu₂Au₂, Ag₇Cu₂Au₄, Ag₅Cu₂Au₆, Ag₃Cu₇Au₃, Ag₃Cu₃Au₇, Ag₁Cu₉Au₃, Ag₁Cu₆Au₆, and Ag₁Cu₃Au₉ clusters are identified as more stable than their neighboring clusters, based on the excess energy and second-order difference energy. Regarding the electronic properties, all ternary clusters exhibit reduced HOMO–LUMO gaps compared to pure clusters. Notably, the Ag₁Cu₇Au₅ cluster shows the highest ionization potential and the lowest electron affinity, whereas the Ag₈Cu₃Au₂ cluster displays the opposite trend. Regarding the optical properties, most 13-atom Au-Ag-Cu ternary clusters demonstrate a red shift relative to pure clusters, with absorption spanning from the visible to the near-UV region. Of the Au-Ag-Cu ternary clusters investigated here, the Ag₆Cu₁Au₆ cluster exhibits the strongest absorption peak at 314.70 nm, whereas the Ag₅Cu₃Au₅ cluster shows the strongest absorption in the visible region. This study identified significant factors affecting the stability of Au-Ag-Cu ternary clusters, providing direction for future research on the stability of more complex ternary clusters. Investigation of optical properties offers a theoretical basis for the prospects of Au-Ag-Cu ternary clusters as optoelectronic materials.

Stimulated by the experimental observation of fullertube [Journal of the American Chemical Society. 2020, 142, 15,614–15,623], a systematic density functional study of the structures and the growth pathway of [6] fullertube C_36+36+12n series is performed. Starting from D_6d(1)–C₇₂, D_6h(24)–C₈₄ can be described as consisting of two end-caps (half of D_6d(1)–C₇₂) attached to a C₁₂ carbon ring. Potential energy surface calculations reveal that the optimal pathway for this growth process proceeds via six sequential and directional C₂ insertions involving metastable heptagonal-ring intermediates and avoiding high-energy-barrier Stone–Wales rearrangements. These findings offer critical insight into the self-assembly mechanism of fullerene-based nanostructures and establish a theoretical basis for the rational design of tunable carbon nanomaterials.

Metal/graphene heterostructures are of great interest for use in electrocatalysis, electrochemical biosensors and graphene electrografting, making it important to understand the charge redistribution features at the metal/graphene/electrolyte interface to explain and predict their electrochemical properties. In this work, using grand-canonical DFT, the charge distribution in few-layer graphene supported on Au and Pt substrates is obtained as a function of the electrode potential and the number of graphene layers. It is shown that graphene coating on the metal surface shifts the potential of zero charge towards more negative values. A phenomenological model for describing charge distribution in the studied systems is proposed and parameterized based on DFT calculations. It can be used as a charge model for the force field intended for MD simulation of electrolytes near the electrified metal/graphene heterostructures at a fixed potential relative to the standard hydrogen electrode. The results can be used for explaining, predicting and optimizing electrochemical catalysts and biosensors based on the metal/graphene heterostructures.

The number of carbon allotropes is ever increasing with a variety of novel network topologies. Among several that were recently proposed, the K₄ structure draws particular attention due to its similarities with diamond, but it is a chiral periodic graph. However, the proposed K₄ was shown to be dynamically unstable. As a result, despite the fact that such a graph is uncommon in the allotropes of elements, the graph of K₄ is disregarded as a potential structure for elemental carbon. Herein, by means of first principles calculations, we have attempted stabilizing such a chiral graph for carbon by modulating phonon eigenvectors associated with imaginary phonon frequencies that were responsible for the structure instability. This has led us to generate six novel stable carbon allotropes, with 4- and a mix of 3,4-connected carbon atoms, that have the history of chiral K₄. The newly predicted carbon allotropes retain chirality, exhibit lower symmetry than K₄ carbon, and show improved thermodynamic stability. Among these, the thermodynamic stability increases as the ratio of 3:4 connectedness decreases. Analysis of the electronic structure suggests that the 3-connected K₄ net would prefer to be colored with elements of three valence electrons. The computed band gap suggests that all the six novel K₄ modifications predicted are semiconductors with band gaps ranging from 0.72 to 5.14 eV. In addition, the calculated elastic stiffness constants indicates that the K₄ carbon modifications are mechanically stable.

Identifying the most stable, or global-minimum (GM), structure of coordination complexes is critical across numerous scientific fields. In this work, we developed a new program called the SGMCC package, designed to search for the most stable structures of coordination complexes containing single-core or multi-cores metal centers. We introduced several improvements to the traditional genetic algorithm (GA), including the integration of isomer-specific chemical constraints, alongside the random perturbation (RP) algorithm followed by the geometry relaxation (GR) algorithm. The SGMCC package facilitates the study of micro-scale coordination structures formed by metal ions bound to ligands, with applications in areas such as seawater uranium extraction, rare earth element extraction and separation, and the separation of lanthanides/actinides and other nuclides. Additionally, the SGMCC program can accelerate the discovery of new ligands and materials for metal extraction and separation, investigate nucleation mechanisms, and analyze the dynamic structural evolution of metal complexes during nucleation. This paper presents an overview of the SGMCC package's applications.