The energy losses of protein ions passing through a collision cell filled with inert gas have been modeled as the aerodynamic drag on a projectile at high Knudsen number. When applied to the energy loss data of Covey and Douglas (J. Am. Soc. Mass Spectrom.1993, 4, 616-623) with drag coefficients from the gas dynamics literature, derived protein cross sections are ∼0.8 of those found with the simple collision model used by Covey and Douglas. © 1994 American Society for Mass Spectrometry.
Douglas, D. J. (1994). An aerodynamic drag model for protein ions. Journal of the American Society for Mass Spectrometry, 5(1), 17–18. https://doi.org/10.1016/1044-0305(94)85079-8