Deposition mode ice nucleation reexamined at temperatures below 200 K

E. S. Thomson, X. Kong, P. Papagiannakopoulos, J. B. C. Pettersson
2014 Atmospheric Chemistry and Physics Discussions  
The environmental chamber of a molecular beam apparatus is used to study deposition nucleation of ice on graphite, alcohols and acetic and nitric acids at temperatures between 155 and 200 K. The critical supersaturations necessary to spontaneously nucleate water ice on six different substrate materials are observed to occur at higher supersaturations than are theoretically predicted. This contradictory result motivates more careful examination of the experimental conditions and the underlying
more » ... nd the underlying basis of the current theories. An analysis based on classical nucleation theory supports the view that at these temperatures nucleation is primarily controlled by the rarification of the vapor and the strength of water's interaction with the substrate surface. The technique enables a careful probing of the underlying processes of ice nucleation and the substrate materials of study. The relevance of the findings to tropospheric temperatures is discussed.
doi:10.5194/acpd-14-23711-2014 fatcat:glo5nxzdsveahicgj7hcirxk34