arXiv subjects

Peter Ludwig Rodríguez-Kessler

Publications and source records attributed to Peter Ludwig Rodríguez-Kessler.

9 recordsLinked to original sources

arXiv2026

Structural prediction of B$_{18}$Y$_{2}$ cluster: A Machine-Learning-Assisted Basin-Hopping Study

The structural and optical properties of the doubly yttrium-doped boron cluster B$_{18}$Y$_2$ have been systematically investigated using density functional theory calculations. The lowest-energy structure was identified through extensive basin-hopping searches accelerated by a pre-trained MACE machine-learning potential and subsequently refined and validated at the DFT level. The resulting global-minimum structure adopts a double-ring geometry, consisting of two fused B$_9$ rings stabilized by yttrium atoms positioned above and below the boron framework. Vibrational frequency calculations confirm the dynamical stability of the optimized structure, while the calculated infrared and UV--Vis spectra provide characteristic signatures of the Y--B interactions and the electronic structure of the boron framework. These results demonstrate how yttrium doping can stabilize unusual double-ring boron architectures and highlight the effectiveness of machine-learning-assisted basin-hopping searches for exploring the complex potential-energy landscapes of doped boron clusters.

cond-mat.mtrl-sci↗

arXiv2026

Structure Prediction and Bonding Analysis of B$_{18}$Ag$_2$ Clusters Featuring Double-Ring Motifs

The structural stability, electronic structure, and bonding characteristics of the silver-doped boron cluster B18Ag2 were investigated using density functional theory (DFT) combined with global optimization techniques. Basin-hopping searches identify a bent double-ring structure as the global minimum, consisting of two stacked B9 rings symmetrically stabilized by Ag atoms located above and below the boron framework. The UV-Vis absorption spectrum exhibits weak transitions in the near-infrared region and intense bands in the visible and near-ultraviolet regions, reflecting delocalized electronic excitations within the boron framework. Charge analysis indicates moderate electron redistribution from Ag atoms to the boron scaffold. Real-space bonding analyses based on the electron localization function (ELF), reduced density gradient (RDG), and molecular electrostatic potential (MEP) reveal that bonding is dominated by {$σ$}-delocalization over the boron skeleton, while Ag-B interactions are weak, non-directional, and primarily electrostatic. The continuous annular electron delocalization within the double-ring structure suggests an aromatic-like character. These findings establish B18Ag2 as a silver-stabilized boron double-ring cluster in which global electron delocalization governs structural stability, while Ag atoms act as axial stabilizing centers that modulate the electronic structure. This work provides new insight into the role of coinage-metal doping in stabilizing extended boron nanostructures.

cond-mat.mtrl-sci↗

arXiv2026

Charge, Bonding, and Optical Properties of the B$_7$Ca$_2$ Cluster: An Alkaline-Earth Dimer Stabilized by a Single Boron Ring

The charge, bonding, and optical properties of the calcium-doped boron cluster B$_7$Ca$_2$ have been systematically investigated using density functional theory calculations. Extensive global basin-hopping searches identify a single-ring B$_7$ geometry stabilized by two calcium atoms symmetrically located on opposite sides of the boron ring as the global minimum. Electronic structure analysis reveals pronounced charge redistribution and strong Ca--B interactions that promote electron delocalization over the boron framework. Hirshfeld charge analysis indicates substantial electron donation from the electropositive calcium atoms to the electron-deficient B$_7$ ring, leading to effective electronic stabilization without the involvement of transition-metal $d$ orbitals. Optical absorption spectra further reflect the delocalized nature of the frontier electronic states. Real-space bonding analyses based on the electron localization function (ELF), Interaction Region Indicator (IRI), and the Laplacian of the electron density reveal a multicenter bonding pattern dominated by electron delocalization within the boron ring, with calcium acting primarily as an electrostatic and charge-donating stabilizer rather than forming localized two-center Ca--B bonds. These results establish B$_7$Ca$_2$ as a prototypical example of an alkaline-earth-metal-stabilized boron ring and highlight the ability of non-transition metals to stabilize aromatic boron clusters through charge transfer and multicenter bonding.

cond-mat.mtrl-sci↗

arXiv2025

Revisiting and Accelerating the Basin Hopping Algorithm for Lennard-Jones Clusters: Adaptive and Parallel Implementation in Python

We present an adaptive and parallel implementation of the Basin Hopping (BH) algorithm for the global optimization of atomic clusters interacting via the Lennard-Jones (LJ) potential. The method integrates local energy minimization with adaptive step-size Monte Carlo moves and simultaneous evaluation of multiple trial structures, enabling efficient exploration of complex potential energy landscapes while maintaining a balance between exploration and refinement. Parallel evaluation of candidate structures significantly reduces wall-clock time, achieving nearly linear speedup for up to eight concurrent local minimizations. This framework provides a practical and scalable strategy to accelerate Basin Hopping searches, directly extendable to ab initio calculations such as density functional theory (DFT) on high-performance computing architectures.

cond-mat.mtrl-sci↗

arXiv2025

Size-Dependent Structural Motifs in Ag$_n$Mo (n = 2-13) Clusters: From Planar to Icosahedral Architectures

We present a comprehensive density functional theory (DFT) study of Mo-doped silver clusters Ag$_n$Mo ($n=1$-14), focusing on their structural, electronic, and bonding properties. Global optimization reveals an evolution from planar and low-symmetry isomers in small clusters to compact three-dimensional geometries with higher symmetry, culminating in a highly stable icosahedral structure at $n=12$. Binding energy and second-order energy difference analyses identify $n=12$ as a "magic number" cluster exhibiting enhanced thermodynamic stability and a pronounced HOMO-LUMO gap, indicative of electronic shell closure. Bond length analysis shows relatively constant Ag-Mo distances alongside a size-dependent increase in Ag-Ag bond lengths, reflecting the growth of metallic bonding networks. Hirshfeld charge analysis reveals significant charge transfer from Ag to Mo in small clusters, which decreases with size as the system transitions toward delocalized metallic bonding. These findings provide detailed insights into the size-dependent interplay of geometry, bonding, and electronic structure in Ag$_n$Mo clusters, with implications for their catalytic and material applications.

cond-mat.mtrl-sci↗

arXiv2025

Inverse Sandwich Geometry and Stability of B$_7$Y$_2$ Clusters: A DFT Study

In this work, we use density functional theory (DFT) to investigate the structural and electronic properties of B$_7$Y$_2$ clusters -- boron frameworks doped with two yttrium atoms. Our results show that the most stable configuration adopts an inverse sandwich geometry, while higher-energy isomers ($\sim$1.45 eV above) exhibit B$_7$ wheel-like motifs with yttrium at top or bridge sites. To understand the bonding and stability, we analyze the electron localization function (ELF) and localized orbital locator (LOL) maps. The global minimum shows a symmetric, delocalized electron distribution, strong B-B covalent bonding, and partial charge transfer from Y atoms. In contrast, higher-energy isomers show less effective Y-B interactions. ELF and LOL analyses confirm electron delocalization within the boron framework. Mulliken population analysis reveals significant metal-to-boron charge transfer, contributing to the stability of the inverse sandwich structure through synergistic effects of delocalized bonding and charge redistribution.

cond-mat.mtrl-sci↗

arXiv2025

Stability and reactivity of double icosahedron Ag$_{17}$M$_2$ (M=Ni, Cu, Zn) clusters

Herein, the structure and stability of double icosahedron Ag$_{17}$M$_2$ (M = Ni, Cu, Zn) clusters are investigated using density functional theory (DFT) computations. The results indicate that the clusters favor endohedral configurations in the doublet state, as confirmed with four different functionals: BP86, PBE0, B3PW91, and TPSSh. Additionally, the doped clusters exhibit higher ionization energies and electronegativities compared those of the bare Ag$_{19}$ cluster. After doping, the ELF function increases at the Ag sites, which reveals important implications for catalysis.

physics.atm-clus↗

arXiv2024

Vibrational and electronic properties of the B$_7$Al$_2$ cluster

In this work, we employ density functional theory (DFT) to explore the structure of boron clusters doped with two aluminium atoms (B$_7$Al$_2$ or Al$_2$B$_7$). The results show that the most stable structure is a bipyramidal configuration formed by a B$_7$ ring coordinated with two Al atoms, while the higher energy isomers correspond to peripheral Al$_2$-doped B$_7$ structures. The IR spectra and density of states reveal remarkable differences between the global minimum and the higher energy isomers.

cond-mat.mtrl-sci↗

arXiv2024

Vibrational and electronic properties of Al$_{12}$M (M=Cu, Zn) clusters: DFT calculations

In this work, the vibrational and electronic properties of Al$_{12}$M (Zn, Cu) clusters are investigated using density functional theory (DFT) calculations. The results indicate that the clusters favor low-spin states when evaluated with three different functionals: PBE, PBE0, and TPSSh. Additionally, the doped clusters exhibit lower ionization energy and electron affinity compared to the neutral Al$_{13}$ cluster. The density of states show a higher degree of hybridization in Al$_{12}$Cu compared to Al$_{12}$Zn.

cond-mat.mtrl-sci↗