[CPMD-list] how to do constraint optimization?

[Axel Kohlmeyer]

On Wed, 7 Dec 2005, Lan-Feng Yuan (lyuan at Princeton.EDU) wrote:

LY>   Dear Axel,
LY> 

LY>   Do you propose to run a simulated annealing MD with constraint to
LY> find some nearly optimized structure, then run constraint
LY> optimization? First I didn't know simulated annealing MD can run
LY> with constraint, thank you ... But I doubt it's much helpful,


LY> because I already have the fully optimized structure (i.e., without
LY> constraint), then change the atom 1-2 distance a bit, so the start
LY> geometry should not be too far from constraint optimized structure.
LY> But it still runs for thousands of steps without a conclusion.

do you want to say, that the geometry optimization does not converge?
that may be simply due to the way the convergence is computed (i.e.
it may not ignore the constraint forces properly). does the geometry
change significantly?

axel

LY> 
LY>   Thanks! Regards,
LY> 
LY>   Lan-Feng
LY> 

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