Fig. 6: Ion emission mechanism.
From: Nanopore ion sources deliver individual ions of amino acids and peptides directly into high vacuum
a Plot of the cumulative probability that an emitted amino acid with a small hydration shell (radius = 7 Å) will collide with an evaporated water molecule or background gas molecule as a function of distance from the meniscus, r. The green curve shows the calculated maximum water vapor density as a function of the distance from the meniscus. b Diagram of the potential energy, U(r), showing the contributions to the energy barrier for ion evaporation: the solvation energy, ΔG0, image charge attraction, Uimage, and electrostatic repulsion, UE. \({r}_{\max }\) represents the distance from the meniscus where the potential energy is highest. G(E) is the reduction in the energy barrier height due to the presence of an electric field of magnitude E. c Plot of the approximate limiting fields for ion evaporation and droplet generation (Rayleigh limit). The region where ion evaporation should dominate is highlighted in green. Source data are provided as a Source Data file.
