Electron detachment energies of PbN−(N=24–204) determined in a simple magnetic bottle photoelectron spectrometer

A simple magnetic bottle time-of-flight photoelectron spectrometer is constructed and used to measure the vertical detachment energies (VDE) of large lead clusters. The main feature of the spectrometer is a high transmission for low kinetic energy electrons, accompanied by a reasonable resolution. The measured VDE of the lead clusters are compared to local density approximation calculations in the spherical jellium model. Over the whole size range (N=2, …, 204), the experimental results roughly follow the calculated values. A slight systematic deviation as well as some fine structure in the N-dependence emphasizes that the model used is only a rough approximation to the real situation. The usefulness of the photodetachment method for the detection of large clusters is discussed.