Surface-enhanced Raman scattering investigations of C2nH2 (n=4–6) in as-prepared and dried Ag colloid

Size-selected polyynes synthesised by submerged arc discharge in water

“…All the predicted spectra have been rigidly shifted by 19.5 nm to match the experimental data of C8. Indeed, C8 has been widely studied in previous works [18,30,41,42] and many spectra are available for a comparison, showing a complete agreement with our spectrum. For this reason, we considered it From the absorbance obtained by UV/Visible scanning spectrophotometer measurements and using the Lambert-Beer law with molar extinction coefficients taken from literature [24,25], we estimated the relative fractions of polyynes present in the solution of water/polyynes obtained just after the synthesis and filtration.…”

“…All the predicted spectra have been rigidly shifted by 19.5 nm to match the experimental data of C8. Indeed, C8 has been widely studied in previous works [18,30,41,42] and many spectra are available for a comparison, showing a complete agreement with our spectrum. For this reason, we considered it as a reference system for a reliable determination of the shifting factor applied to the computed spectra.…”

Pseudocarbynes: Linear Carbon Chains Stabilized by Metal Clusters

“…A pseudocarbyne is a combination of an sp-carbon chain and an associated metal atom or cluster and is therefore expected to share many properties with polyynes. The optical signatures of polyynes have received much attention, typically when adsorbed onto Au or Ag nanoparticles to benefit from surface-enhanced Raman scattering (SERS). − Polyynes expedite Ag or Au nanoparticle aggregation, as observed through shifting of plasmon bands , and Raman signals . Although previous efforts have focused on the influence of nanoparticles (>5 nm diameter) on polyynes or on exchanging the terminal hydrogens of polyynes with metal atoms, , such studies also provide evidence in support of a charge-transfer interaction between metals and intact polyyne molecules .…”

“…Figure shows UV–vis spectra from solutions following laser ablation of a graphite or Au target in ethanol. The amplitudes of the UV–vis absorption spectral signatures of the 1 Σ u + ← 1 Σ g + transition, which shift slightly with solvent, − were used to quantify the distribution of polyynes produced from the ablation of graphite in ethanol (Figure a). Short-chain polyynes are most abundant, with the concentrations of other polyynes decreasing exponentially with increasing carbon-chain length.…”

“…Laser ablation in liquids (LAL) is well known for synthesizing polyynes in solution under ambient conditions. − Reportedly, carbyne can also be generated through LAL of ethanol over a gold (Au) target . We proposed instead that the products are linear carbon chains stabilized by noncovalent interactions with subnanometer Au clusters (Figure ).…”