Ionization energies of aluminum-cesium bimetallic clusters (Al_nCs_m)

Aluminum-cesium bimetallic clusters (Al_nCs_m) were produced by the combination of laser vaporization and a high-temperature pulsed nozzle. To investigate their electronic structures, ionization energies (E_iS) of the Al_nCs_m clusters were measured using a tunable ultraviolet laser combined with a time-of-flight mass spectrometer. In general, their E_is decrease by 0.4-1.0 eV with increasing number of cesium atoms, but discontinuous changes in E_is can be also observed, which are attributed to electronic shell structures; completeness of electron shell by the addition of a Cs atom induces high E_i, and an excess electron from the Cs atom results in large E_i, decrement. The electronic stability of the Al_nCs_mclusters can be also examined by their abundance.