Electronic structure of indium phosphide clusters: anion photoelectron spectroscopy of InxPx− and Inx+1Px− (x=1–13) clusters

Photoelectron spectra for indium phosphide (InP) cluster anions comprised of up to 27 atoms were measured at a photodetachment wavelength of 266 nm. Results are presented for cluster anions of both stoichiometric and non-stoichiometric composition (InxPx−, Inx+1Px−; x=1–13). In3P3 exhibits the lowest electron affinity (EA) of all the clusters studied, indicating a particularly stable neutral species. The EAs of the stoichiometric clusters are considerably lower than those of the corresponding non-stoichiometric clusters, suggesting the presence of closed-shell ground states for the neutral InxPx clusters. Remarkable agreement between the experimental EAs and those derived from calculations on quantum dots is found.