Molecule-like and lattice vibrations in metal clusters

Abstract

We report distinct molecule-like as well as lattice (breathing) vibrational signatures of atomically precise, ligand-protected metal clusters using low-temperature Raman spectroscopy. Our measurements provide fingerprint Raman spectra of a series...

Elucidating the Near-Infrared Photoluminescence Mechanism of Homometal and Doped M25(SR)18 Nanoclusters

“…As shown in Figure h, the temperature-dependent linewidth of AuAg 24 can be well fitted by the weak e–ph coupling model given in eq (the last term is neglected since no impurity exists), and Table gives the extracted parameters. The energy of the optical phonon is determined to be 28 meV, which matches well with the vibration energy of Ag 2 (SR) 3 staple motifs determined by Raman spectroscopy . In Figure i, the temperature-dependent linewidth of Au x Ag 25– x is similar to the MAu 24 series, which shows a nonlinear relationship at high temperatures.…”

“…The energy of the optical phonon is determined to be 28 meV, which matches well with the vibration energy of Ag 2 (SR) 3 staple motifs determined by Raman spectroscopy. 59 In Figure 4i, the temperature-dependent linewidth of Au x Ag 25−x is similar to the MAu 24 series, which shows a nonlinear relationship at high temperatures. However, the multiple emitters in Au x Ag 25−x due to different x make it not possible to fit the temperature-dependent linewidth by the strong coupling model.…”

Effect of Silver Alloying on the Vibrational Dynamics of Rod-Shaped Gold Nanoclusters

“…After photoexcitation, the Au 12 Ag 13 rod should also become longer compared to Au 25 , which leads to the unconventionally slower oscillations in Au 12 Ag 13 NCs. (2) In ultrasmall metal NCs, the surrounding protecting ligands can also play an important role in modulating the molecular vibrations . The very low-frequency acoustic vibrations in both NCs could be affected by the surface-protecting ligands, which show different chemical environments before and after silver alloying (attached to silver versus gold).…”

“…The effect of doping on the excited-state lifetimes of Au 13 , Au 38 , Ag 44 , and Au 144 has also been reported recently. ,− Nevertheless, the effect of doping and alloying on coherent vibrations remains largely unknown. Molecular vibrations in metal NCs have been investigated by low-frequency Raman spectroscopy, , while ultrafast spectroscopy can provide additional information on the coherent vibrations . The coherent vibrations of metal cores in metal NCs can be initiated by ultrashort laser pulses, which modulate the transient absorption signals. , Coherent vibrations in metal nanoparticles and semiconductor quantum dots have provided unique information about their mechanical properties. , Therefore, understanding the influence factors on these coherent oscillations of metal NCs can help reveal their mechanical properties as well as energy dissipation mechanisms.…”

“…21,29−31 Nevertheless, the effect of doping and alloying on coherent vibrations remains largely unknown. Molecular vibrations in metal NCs have been investigated by low-frequency Raman spectroscopy, 32,33 while ultrafast spectroscopy can provide additional information on the coherent vibrations. 34 The coherent vibrations of metal cores in metal NCs can be initiated by ultrashort laser pulses, which modulate the transient absorption signals.…”