Photoelectron spectroscopy of silicon-and germanium-fluorine binary cluster anions (Si_nF^-_m, Ge_nF^-_m)

Electronic properties of silicon-fluorine and germanium-fluorine cluster anions (Si_nF^-_m; n = 1-9, m = 1-3, Ge_nF^-_m; n=1-9, m=1-3) were investigated by photoelectron spectroscopy using a magnetic-bottle type electron spectrometer. The binary cluster anions were generated by a laser vaporization of a silicon/germanium rod in an He carrier gas mixed with a small amount of SiF₄ or F₂ gas. Comparison between photoelectron spectra of Si_nF^-/Ge_nF^- and Si^-_n/Ge^-_n (n=4-9) gives the insight that the doped F atom can remove one electron from the corresponding Si^-_n/Ge^-_n cluster without any serious rearrangement of Si_n/Ge_n framework, because only the first peak of Si^-_n/Ge^-_n, corresponding singly occupied molecular orbital (SOMO), disappears and other successive spectral features are unchanged with the F atom doping