From: jos.bergervoet@xs4all.nl   
      
   On 2/13/2018 5:36 PM, charly wrote:   
   > Kerry Soileau wrote:   
   >> If the negative charge on a sphere in a vacuum is increased   
   >> sufficiently, do electrons begin to escape from the sphere into   
   >> vacuum? If so, is the physics similar to that of the photoelectric   
   >> effect work function concept?   
   >>   
   >> Thanks for any references/insight on this question.   
   >>   
   >> [[Mod. note -- I think the answers to your questions are "yes" and   
   >> "yes".  More detailed discussions from the newsgroup would be welcome.   
   >> -- jt]]   
   >   
   > Question : would this problem not be rather similar to a glass, filled   
   > with water, inverted and under gravity? The water falls out, unless its   
   > surface is stabilized by for example a sheet of paper.   
   >   
   > Quantum tunneling of electrons leeds to a formula (Fowler Nordheim). But   
   > its results are reached only for sharp points. For flat surfaces there   
   > is a disagreement with experiment : the field reached is lower by a   
   > factor 10-20, even for well polished surfaces. Stability problem?   
      
   Or maybe polished surfaces are not flat? Even if you have a   
   perfectly stacked crystal, just one single atom adsorbed on   
   its surface would create big field gradients and may already   
   give you the order of magnitude difference you mention.   
      
   --   
   Jos   
      
   --- SoupGate-Win32 v1.05   
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