Emission limited electrostatic atomization and the fine structure constant

Quadropole mass spectrometer measurements are obtained for charged Octoil sprays, at a droplet radius of 0.83 /spl mu/m. Data are obtained for both emission limit and Rayleigh limit regime. The data revealed that operation in the emission limited regime is a function of inverse relative dielectric constant, coupling parameter r/sub s/, and the inverse fine structure constant f. The values r/sub s/ and f and their ratio (r/sub s//f) involve Planck's constant, indicating that emission limited spraying is controlled by quantum mechanical processes. The relationship between the energy per surface charge with the droplet diameter of Octoil is also shown.