Cover Feature: Role of Anharmonicity and Bimetallic Intermixing in the IR and Raman Spectra of Cun$_n$ and Pdn$_n$Cu6−n$_6-n$ clusters (n<7$n \lt 7$). Ab Initio Benchmarking of DFT (Small Struct. 5/2026)

Ab Initio Benchmarking State-of-the-art ab initio benchmarks for Cu and Pd-Cu clusters (up to six atoms) provide reliable harmonic wavenumbers and assess DFT accuracy for IR/Raman spectra. Bonding evolves from molecule-like to delocalized metallic behavior, shaping vibrational spectra. Triplet Pd6 is among the exceptions, requiring a multireference treatment that reveals a Jahn–Teller-distorted octahedral geometry. Validated DFT, including anharmonic effects, enables spectroscopic assignment. More in the Research Article (10.1002/sstr.70450), María Pilar de Lara-Castells and co-workers.