  In this work, we report X-ray photoelectron (XPS) and valence band (VB)
spectroscopy measurements of surfactant-free silver nanoparticles and
silver/linear carbon chains (Ag@LCC) structures prepared by pulse laser
ablation (PLA) in water. Our measurements demonstrate significant oxidation
only on the surfaces of the silver nanoparticles with many covalent
carbon-silver bonds but only negligible traces of carbon-oxygen bonds.
Theoretical modeling also provides evidence of the formation of robust
carbon-silver bonds between linear carbon chains and pure and partially
oxidized silver surfaces. A comparison of theoretical and experimental
electronic structures also provides evidence of the presence of non-oxidized
linear carbon chains on silver surfaces. To evaluate the chemical stability, we
investigated the energetics of the physical adsorption of oxidative species
(water and oxygen) and found that this adsorption is much preferrable on
oxidized or pristine silver surfaces than the adsorption of linear carbon
chains, which makes the initial step in the oxidation of LCC energetically
unfavorable.
