Zero electron kinetic energy spectroscopy of Au−6

Abstract
Zero electron kinetic energy (ZEKE) spectroscopy and photodetachment cross section measurements have been carried out on Au6. The transition frequencies of ZEKE peaks and resonance peaks are nearly identical, consistent with the proposal that the excited negative ion of Au6 has a geometry quite similar to that of neutral Au6, and supporting the picture of the resonances as weakly bound ‘‘surface states.’’ From these studies the 0–0 transition frequency between Au6 and Au6 is measured to be 16 541±17 cm1, and the vibrational frequencies for the neutral Au6 ground state, the Au6 ground state, and the (Au6)* anion excited electronic state are 107, 73, and 107 cm1, respectively. Lastly, we observe evidence for a previously unreported resonance transition to the excited anion which we suggest is the 0–0 transition of Au6 to (Au6)*.