Photoelectron spectra and angular distributions in photodetachment of gold hydride anions AuH(-) and Au(2)H(-) have been obtained using photoelectron velocity-map imaging. Both the images exhibit vibrationally resolved ground state transitions. The adiabatic electron affinities of AuH and Au(2)H are measured to be 0.758(20) and 3.437(3) eV, respectively. Franck-Condon analyses of the AuH spectra determined that the equilibrium bond length of the ground state of AuH(-) is 1.597(6) A. The photoelectron images of Au(2)H(-) show a vibrational progression of 148(4) cm(-1) assigned to the Au-Au stretching mode at the ground state. Ab initio calculation results are in excellent agreement with the experimental results. For the ground state of Au(2)H, a new bent Au-Au-H structure with the angle of 131 degrees is suggested. Moreover, energy-dependent photoelectron anisotropy parameters are also reported and discussed.

Photodetachment of group 11 cyanide anions MCN(-) (M = Cu, Ag, Au) has been investigated using photoelectron velocity-map imaging. The electron affinities (EAs) of CuCN (1.468(26)) and AgCN (1.602(22)) are larger, while that of AuCN (2.066(8)) is smaller than those of the free atoms. This intriguing observation was confirmed by theoretical studies and was assigned to the transition between ionic and covalent bond properties. The harmonic frequencies of the extended vibrational progressions in the M-C stretching mode are 460(50), 385(27), and 502(10) cm(-1), respectively, which suggests a stronger bond for Au-CN than for Ag-CN. Electronic structure analysis and model calculations suggest that all M-C bonds in group 11 cyanides are best described as single bonds. A model has been proposed to explain how the relativistic effects influence the Au-C bond strength in AuCN.

Structural and electronic properties of silver hydride cluster anions (Ag n H − ; n = 1-3) have been explored by combining the negative ion photoelectron imaging spectroscopy and theoretical calculations. The photoelectron spectrum of AgH − exhibits transitions from AgH − 2 + to AgH 1 + and AgH 3 + , with the electron affinity (EA) 0.57(3) eV. For Ag 2 H − , the only observed transition is from Ag 2 H − (C ∞v ) 1 + to Ag 2 H (C 2v ) 2 A and the electron affinity is 2.56(5) eV. Two obvious electron bands are observed in photoelectron imaging of Ag 3 H − , which are assigned to the transitions from Ag 3 H − (C 2v -T, which means C 2v geometry with top site hydrogen) 2 B 2 to Ag 3 H (C 2v -T) 1 A 1 and Ag 3 H (C 2v -T) 3 B 2 . The electron affinity is determined to be 1.61(9) eV. The Ag-H stretching modes in the ground states of AgH and Ag 2 H are experimentally resolved and their frequencies are measured to be 1710(80) and 1650(100) cm −1 , respectively. Aside from the above EAs and the vibrational frequencies, the vertical detachment energies to all ground states and some excited states of Ag n H (n = 1-3) are also obtained. Theoretical calculations reproduce the experimental energies quite well, and the results are used to assign the geometries and electronic states for all related species.