Fluctuation of the number of particles adsorbed on surfaces under the influence of gravity

The fluctuation of the number of particles deposited under a significant gravity field onto systems of finite size is analyzed experimentally and theoretically. In particular, the variance ${\mathrm{\sigma }}^2$ varies as 1-〈α〉${\mathrm{\theta }}^3$+O(${\mathrm{\theta }}^4$) with the coverage θ, where 〈α〉 depends upon the interactions involved in the deposition process. This result is valid for any deposition process in which the gravity is ‘‘strong enough,’’ regardless of the radial distribution function corresponding to the process. This conclusion, of interest to a large class of deposition processes, is supported by original experimental results.