Probing the structures and bonding of Ag/H end-capping acetylene and polyyne, AgC2nH− (n = 1, 2), a combined photoelectron imaging and quantum chemical calculation study

The PES and velocity-map images of the linear anions AgC2nH− (n =1,2) are shown here. [Display omitted] •The PES of anionic AgC2H and AgC4H were obtained.•The electronic configuration of the anions was confirmed.•Bond order and character of Ag-C bond in the neutral species were analyzed. The electronic structures of AgC2nH− (n = 1, 2) are reported by using photoelectron imaging and ab initio calculations. The results indicate that all the ground states of anion and neutral AgC2nH have a linear geometry. The electron affinities (EAs) are measured to be 1.123 and 1.379 eV for AgC2H and AgC4H, respectively. The NRT analysis shows that ionic character dominates the Ag–C chemical bond in these neutral species. The calculated static dipole polarizability (α) and second hyperpolarizability (γ) of the molecules indicate that the cap of Ag could enhance the nonlinear optical responses.