Probing the structures and bonding of auropolyynes, Au (CC)n Au- (n=1-3), using high-resolution photoelectron imaging

We report an investigation of a series of auropolyynes, Au (C C)(n) Au (n = 1-3), using highresolution photoelectron imaging and ab initio calculations. Vibrationally resolved photoelectron spectra are obtained, allowing the electron affinities of Au (C C)(n) Au to be accurately measured as 1.651(1), 1.715(1), and 1.873(1) eV for n = 1-3, respectively. Both the Au C symmetric stretching and a bending vibrational frequency are observed for each neutral auropolyyne. Theoretical calculations find that the ground state of Au2C2 has a linear acetylenic Au C C-Au- structure, whereas the asymmetric Au Au C C structure is a low-lying isomer. However, for Au2C4 and Au2C6, our calculations show that the asymmetric Au Au (C C)(n) isomers are the global minima and the Au (C C)(n) Au symmetric structures become low-lying isomers. All the asymmetric Au Au (C C)(n) isomers are found computationally to have much higher electron binding energies and are not accessible at the detachment photon energies used in the current study. For neutral Au2C2n, the Au (C C)(n) Au auropolyyne structures are found to be the global minima for n = 1-3. The electronic structures and bonding for Au (C C)(n) Au (n = 1-3) are compared with the corresponding Au (C C)(n) and Au (C C)(n) H species. Published by AIP Publishing.