[CPMD-list] CONVERGENCE CRITERIA FOR GEOMETRY OPTIMIZATION

[Axel Kohlmeyer]

On Wed, 18 Apr 2007, liu liuxiandong wrote:

XL> Dear CPMDers,
XL> 
XL> In an OPTIMIZE GEOMETRY test, I set the
XL> CONVERGENCE GEOMETRY to be 2.0D-5. But, I found that it continued to run
XL> when the output terms (GEMAX, CNORM, DETOT) were all lower than 2.0D-5.
XL> Then, what does the CONVERGENCE GEOMETRY work for ?

the check is against GNMAX.

XL> I also want to fix the CELL during the OPTIMIZE GEOMETRY, that is, only
XL> optimize the positions of ions but keep the volume and shape of the CELL.
XL> How to tell CPMD to do this ?

the cell is fixed by default. 
in fact, trying to optimize the positions _and_ the cell
is pretty complicated (if it works at all).

cheers,
  axel.

XL> Thanks for any suggestions.
XL> 
XL> BEST
XL> 
XL> XIANDONG LIU
XL> 

-- 
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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