  The strategy of using the definition of work function from photoelectric
effect to determine precise and reliable work function by the contribution of
frequency to photoelectric yield is investigated theoretically in this paper.
Based on the Fermi-Dirac distribution and the definition of work function
proposed by Einstein in photoelectric effect, a typical numerical method is
pursed step by step to quantitatively analyze the frequency-dependent
photoelectric yield. Supplementing applications to In14 cluster and three kinds
of metals, the simulations agree well with the observed spectra (photoelectric
yield-frequency). At the same time, the threshold frequency of light-dependent
the work function is theoretically explained successfully via one equation so
that the work function can be predicted precisely and reliably. These results
suggest that the formalism pursed in this paper, which is straight forward and
physical, may be of significant utility in metal cluster spectroscopy. It is
hoped also that the results will encourage a comprehensive theoretical analysis
of the applicability of bulk-derived models to cluster photo-ionization
behavior, and of the transition from atomic and molecular-type to surface-type
photoemission.
