Dipole-bound and valence excited states of AuF anions via resonant photoelectron spectroscopy

Gold fluoride is a very unique species. In this work, we reported the resonant photodetachment spectra of cryogenically cooled AuF− via the slow-electron velocity-map imaging method. We determined the electron affinity of AuF to be 17 976(8) cm−1 or 2.2287(10) eV. We observed a dipole-bound state with a binding energy of 24(8) cm−1, a valence excited state with a binding energy of 1222(11) cm−1, and a resonant state with an energy of 814(12) cm−1 above the photodetachment threshold. An unusual vibrational transition with Δn = −3 was observed in the autodetachment from the dipole-bound state. Moreover, two excited states of neutral AuF were recognized for the first time, located at 13 720(78) cm−1 and 16 188(44) cm−1 above the AuF ground state.