Solvent effects on the structures and binding energies of arsine clusters (AsH3)n (n = 2–6): a DFT study with implicit solvation

Cooperative stability, many-body expansion, and σ-aromaticity of (LiH)n clusters (n = 1-6): A CCSD(T) study at the complete basis set limit.

We investigated the energetics and bonding of lithium hydride clusters (LiH)n (n = 1-6) using a composite ab initio scheme inspired by W2 theory to achieve sub-kcal/mol accuracy. This approach combines CCSD(T) results extrapolated to the complete basis set limit with a rigorous treatment of core-valence correlation, scalar relativistic effects, and the diagonal Born-Oppenheimer correction. Our results show that while Hartree-Fock theory captures the primary electrostatic binding, correlation effects are crucial for determining the energetic preference of compact isomers over cyclic rings. A parallel density functional theory study shows that while standard hybrid functionals like B3LYP-D4 and M06-2X exhibit larger deviations, the double-hybrid revDSD-PBEP86-D4 functional closely matches our benchmarks, delivering sub-kcal/mol accuracy. Structural and chemical bonding analyses, including intrinsic bond orbital, nucleus-independent chemical shift, and many-body expansion (MBE) methods, reveal high ionic character and multi-center bonding (3c-2e and 4c-2e) within the (LiH)n clusters. MBE analysis of the interaction energy of the monocyclic clusters with respect to the LiH molecules reveals that the two- and three-body terms are consistently negative (stabilizing), while all higher-order terms are negligible. We find that σ-aromaticity in these systems is predominantly local and bond-centered. As the rings expand, the interior becomes magnetically decoupled from the σ-skeleton, precluding the formation of a global ring current. These results establish definitive benchmarks for the stability of prototypical electron-deficient clusters.

From Exposed to Encapsulated: Structural Evolution and Enhanced Stability of Sn-Doped Gold Clusters, SnAu n ( n = 2–20), Revealed by DFT

A systematic density functional theory (DFT) investigation was conducted to explore the geometric evolution, electronic properties, and relative stability of tin-doped gold clusters SnAun (n = 2–20). The lowest-energy structures were identified using the CALYPSO structure prediction method and refined at the B3PW91/LANL2DZ level of theory. Our results reveal a distinct size-dependent structural transition: small clusters (n ≤ 8) adopt simple polyhedral geometries (some nearly planar, others three-dimensional) with Sn at peripheral sites, while larger clusters (n ≥ 9) evolve into three-dimensional structures with the Sn atom progressively encapsulated within the Au framework, achieving high coordination in tetrahedral or polyhedral cages for n ≥ 15. Analysis of the average binding energy, second-order difference energy, and HOMO–LUMO gaps identifies SnAu4, SnAu8, and SnAu16 as magic-number clusters with enhanced stability. Natural bond orbital (NBO) analysis suggests significant charge transfer from the electropositive Sn atom to the Au matrix. Theoretical infrared and Raman spectra were simulated, providing distinct vibrational fingerprints that evolve from sharp peaks in small clusters to broad, complex bands in larger systems. Quantum theory of atoms in molecules (QTAIM) analysis suggests that the bonding is predominantly closed-shell (ionic/metallic), with Sn–Au bonds showing enhanced polarization compared with Au–Au bonds. A possible weak localized character in the smallest clusters cannot be excluded, but the overall framework remains closed-shell dominated.

Theoretical analysis on the structural, electronic, and intermolecular interaction features of the CL20/1-AMTN cocrystal

Structural Evolution, Electronic, Bonding, and Magnetic Properties of Ti2Bn (n = 2-16) Clusters: A Computational Study.

The structural evolution, bonding characteristics, and electronic and magnetic properties of Ti2Bn (n = 2-16) clusters have been systematically investigated. The results reveal that small clusters (n = 2-5) adopt open inverse-sandwich structures, while perfect inverse-sandwich configurations are formed at n = 6 and 7. For larger sizes, the clusters evolve into extended inverse-sandwich structures. Population analysis indicates that both Ti atoms carry positive charges, suggesting electron transfer from the Ti atoms to the boron framework. The HOMO-LUMO gaps of Ti2B6 and Ti2B7 exhibit notably large values for alpha electrons, indicating enhanced electronic stability. The average binding energies increase monotonically with cluster size, reflecting greater stability for larger clusters. Second-order energy differences identify n = 4, 7, and 12 as magic numbers. AdNDP analysis of three representative clusters, Ti2B6, Ti2B7, and Ti2B16, reveals that BB two-center two-electron σ bonds are present in Ti2B6 and Ti2B7 but absent in Ti2B16. Instead, multicenter σ and π bonds involving both Ti and B atoms are prevalent. Regarding magnetic properties, clusters with sizes n = 8, 10, 12, and 14 are nonmagnetic, while the others exhibit either ferromagnetic or antiferromagnetic behavior.

Structure Prediction, Bonding Analysis, and Stability of Small Lithium-Nitrogen Clusters LixNy (x + y=6): A Computational Investigation

DFT-based analysis of the structural, electronic, optical, mechanical and thermodynamic characteristics of Rb 2 YAuX 6 (X = Br, Cl) double perovskites for energy conversion applications