Dear Juan,

During the SCF, the fitted density is used.
In the meta-GGA part of the code, the exact (not fitted) density and
derivatives are used.
Another difference is that the meta-GGA number is obtained from
molecular
and atomic calculations in different numerical integration grids,
whereas the same grid
is used in the "SCF number".

This differences may lead to small differences like the one you mention.

If you increase the size of the grid and the size of the fit set, the
differences should go down to zero.

Best regards,
Stan

On Sep 8, 2004, at 7:33 PM, Juan María García Lastra wrote:

> Dear ADF-users:
>
>  
>
> When Metagga key is used a list of energies (calculated post-SCF) for
> each xc potencial is shown. In this list it also appears the energy
> for the xc potential that has been used during the SCF cycle. I have
> used PW91 and I have checked that the Total Bonding Energy and the
> energy for PW91 in the metagga list are different (the difference
> between this two values is about 0.2 eV). It happens the same with
> other functionals. What is the origin of this difference? Is it a bug?
>
>  
>
> Thanks in advance.
>
>  
>
Dr. S.J.A. van Gisbergen      
Scientific Computing & Modelling NV
Theoretical Chemistry, Vrije Universiteit
De Boelelaan 1083
1081 HV Amsterdam
The Netherlands                              
T: +31-20-4447626    
F: +31-20-4447629        
vangisbergen_at_scm.com  
http://www.scm.com
Received on 2004-09-09 12:02:30