Modeling the Photo-Absorption Properties of Noble Metal Nanoclusters: A Challenge for Density-Functional Theory

Modeling the emergence of plasmon resonance in noble metal nanoclusters is still a challenge to overcome for theoretical chemistry. The systems are indeed too small neglect quantum-size effects but large be easily addressed with quantum mechanics. We test here robust answer this open question: simplified variant time-dependent density-functional theory (TDDFT). Applied extended systems, electronic structure-based method succeeds computing sufficient number excitations cover plasmon-like states. By employing it under semilocal exchange-correlation approximation such as PBE, we show that most intense absorption band, which could wrongly assigned has strong interband character. suspect low energy gap between (n–1)d and ns valence orbitals origin d-contamination excitations. demonstrate however global or range-separated hybrid PBE0 RSX-PBE0 problem. notice both approximations not able solve at same time positioning intensity being more accurate intensity. All all, warn user random choice opens door getting correct wrong reason.