Photoelectron spectroscopy of Al<i>n</i>S1− clusters (<i>n</i>=1−9)

Abstract

Photoelectron spectra of AlnS−1 (1≤n≤9) cluster anions were measured at the photon energies of 3.49 and 4.66 eV, using a magnetic bottle electron spectrometer having ∼60 meV resolution. AlS− has an electron affinity of as large as 2.6 eV, attributed to large stability by six bonding electrons. A new electronic state, A′ 2Π, was found 0.4 eV above the AlS ground state, which is in agreement with theoretical calculations. AlnS−1 cluster anions are produced efficiently up to n=5, but the production of larger cluster sizes is found difficult. The mass distribution of AlnS−1 cluster anions and electron binding energy can be explained by a geometric structure obtained by theoretical calculation.