Localized surface plasmon

Transition metal

Surface plasmon resonance

Plasmon

Optics

Physics

Absorption (acoustics)

Surface plasmon

Resonance (particle physics)

Nanoparticle

Chemical physics

Catalysis

Femtosecond

Nanotechnology

Organic chemistry

Excited state

Atomic physics

Chemistry

Materials science

Nanoclusters

Optoelectronics

Laser

Metal

Biochemistry

Journal of the American Chemical Society

The optical properties of metal nanoparticles have attracted wide interest. Recent progress in controlling nanoparticles with atomic precision (often called nanoclusters) provide new opportunities for investigating many fundamental questions, such as the transition from excitonic to plasmonic state, which is a central question in metal nanoparticle research because it provides insights into the origin of surface plasmon resonance (SPR) as well as the formation of metallic bond. However, this question still remains elusive because of the extreme difficulty in preparing atomically precise nanoparticles larger than 2 nm. Here we report the synthesis and optical properties of an atomically precise Au279(SR)84 nanocluster. Femtosecond transient absorption spectroscopic analysis reveals that the Au279 nanocluster shows a laser power dependence in its excited state lifetime, indicating metallic state of the particle, in contrast with the nonmetallic electronic structure of the Au246(SR)80 nanocluster. Steady-state absorption spectra reveal that the nascent plasmon band of Au279 at 506 nm shows no peak shift even down to 60 K, consistent with plasmon behavior. The sharp transition from nonmetallic Au246 to metallic Au279 is surprising and will stimulate future theoretical work on the transition and many other relevant issues.

Sharp Transition from Nonmetallic Au<sub>246</sub> to Metallic Au<sub>279</sub> with Nascent Surface Plasmon Resonance

Sharp Transition from Nonmetallic Au246 to Metallic Au279 with Nascent Surface Plasmon Resonance

Sharp Transition from Nonmetallic Au₂₄₆ to Metallic Au₂₇₉ with Nascent Surface Plasmon Resonance