[Wien] 2 ways to calculate bindning energy

[Lyudmila Dobysheva]

> >>> Fri, 14 Mar 2008 B. Yanchitsky has written:
> Atom name     Z     E[1]-E[i] (eV)
>     Be(hcp)    4      -4.01952760
>     Al(fcc)   13      -9.1210168
>     Cu(fcc)   29     -32.5998664
>     Au(fcc)   79     -57.3670440
> this is just wrong, interatomic potential is something like 0.01-0.1 eV,
> and been multiplied by number of nearest neighbors, something like 10,
> gives 0.1-1 eV (1000K-10000K), but not a million of kelvins.
> I don't think this may be related to DFT, there is some spurious term
> (electrostatic?) that pushes energy up on large volumes.

We have discussed this problem, and came to conclusion that this is connected 
with the energy zero determination. In the high-level mathematical physics, 
there is a theorem that asserts: increase of the periodical cell size with a 
single atom does not give the actual zero, and cannot be compared with a real 
isolated atom moved to infinity. The periodicity itself, irrespective of the 
dimensions, essentially changes the situation. In order to solve the problem, 
a real infinity must be inserted into a calculational scheme. Green's 
function method declares that it can in some variations.

Best regards
Lyudmila Dobysheva
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