Absolute separation energies for Na clusters - art. no. 013202

Na clusters in the size range of 50-400 atoms are led to evaporate in a hea t bath with controlled temperature. For cluster sizes around closed shells, decay rates are determined as a function of temperature. For temperatures below 357 K they all agree with an Arrhenius law and allow absolute separat ion energies to be extracted. Separation energies are presented and compare d to previously determined (relative) values. Enhanced shell effects are ob served in the heat bath experiments. Deviations from the Arrhenius law at i ntermediate temperatures are discussed.