The ABINIT Users Mailing List ( CLOSED )

[James Johns <jej7x@xenon.cchem.berkeley.edu>]

Ok, so I'm going partially off of the tutorials here, but I'm attempting 
to approximate the workfunction of Magnesium(0001) surfaces.  I've 
attatched a sample input file.  My problem is that despite all attempts to 
better optimize the convergence critea based on nband, ecut, the kpt grid, 
or anything, it's underestimating the workfunction by roughly a factor of 
two.  I'm using the fermi level energy level from a 10 atom slab 
calculation as the workfunction.  Is there something wrong with this? 
When I do this for the Ag(111) surface, my estimation is roughly 
100-200meV higher than the experimental version.  The fact that it's only 
slightly more ( and seems to converge based on typical paramters such as 
size of vaccuum spacing etc), while on Mg it is severely less makes me 
think that it's not something inherent in the LDA (or GGA) approximation. 
Does anyone have any thoughts, or alterations to the input file to correct 
for something I'm doing stupidly?
Thanks a lot,
--James Johns
UC Berkeley
Charles Harris group member