PHOTOELECTRON-SPECTROSCOPY AND MASS DISTRIBUTIONS OF ALUMINUM-SULFUR CLUSTER ANIONS (ALNSM-)

Photoelectron spectra of AlnSm- cluster anions (0 less than or equal t o n, m less than or equal to 10) were measured at photon energies of 3 .49 and 4.66 eV, by using a magnetic bottle electron spectrometer. The AlnSm- clusters were produced by laser vaporization of an aluminum-su lfur mixed rod in He carrier gas. The abundant AlnSm- clusters are thr ee types of AlS-(Al2S3)(k), AlS2-(Al2S3)(k), and (Al2S3)(k)(-), where an unit of Al2S3 aggregates with ion cores of AlS-, AlS2-, and Al2S3-, respectively. Al3S3- is exceptionally stable with its geometrical str ucture.