Re: IONS/vacuum pedagogy

[Joseph Bellina <jbellina@saintmarys.edu>]

The range of the bound  electrons outside the plane of the outer ion 
cores is, as I recall a nm or so.  The density falls off rapidly with 
distance from that plane.  However the charge separation causes a surface 
dipole which contributes to the work function associated with the 
surface.  As a result, the value of the workfunction varies with the 
degree of surface roughness and the contours created by the underlying 
crystal.  Thus the (100) surface has a different workfunction than the 
(110).  Both have larger workfunctions than the more rough (211).  By the 
way I thinking in terms of a bcc lattice as in Wolfram, ups pardon me, 
Tungsten.

cheers

On Thu, 15 Oct 1998, Ludwik Kowalski wrote:

> Sorry for the "vavuum" instead of "vacuum", in the subject
> line. If the proposed explanation is acceptable (not conflicting
> with known facts or theories) then one may be able to say that
> electrons on the surface of a metallic sphere near a room
> temperature are also a "space charge".  A thin cloud called
> layer instead of a thicker one  at 2000 K.