关键词: plasmon hybridization, molecular plasmon, time-dependent density functional theory (TDDFT)

Abstract: Relationship of plasmonic properties of multiple clusters to molecular interactions and properties of a single cluster or molecule have become increasingly important due to the continuous emergence of molecular and cluster devices or systems. A hybrid phenomenon similar to plasmonic nanoparticle hybridization exists between two molecules with plasmon excitation modes. We use linear-response time-dependent density functional theory, real-time propagation time-dependent density functional theory, the plasmonicity index, and transition contribution maps (TCMs) to identify the plasmon excitation modes for the linear polyenes octatetraene with -OH and -NH₂ groups and analyze the hybridization characteristics using charge transitions. The results show that molecular plasmon hybridization exists when the two molecules are coupled. The TCM analysis shows that the plasmon modes and hybridization result from collective and single-particle excitation. The plasmon mode is stronger, and the individual properties of the molecules are maintained after coupling when there is extra charge depose in the molecules because the electrons are moving in the molecules. This study provides new insights into the molecular plasmon hybridization of coupled molecules.

Key words: plasmon hybridization, molecular plasmon, time-dependent density functional theory (TDDFT)