[CPMD-list] how to do constraint optimization?

[Axel Kohlmeyer]

On Tue, 6 Dec 2005, Lan-Feng Yuan (lyuan at Princeton.EDU) wrote:

LY>   Dear CPMD users,

dear lan-feng,

LY>   I want to optimize a structure under a constraint, e.g., the
LY> distance between atoms 1 and 2 must be 3 A. According to manual, the
LY> way is to add CONSTRAINTS ... END CONSTRAINTS in &ATOMS. Emm ... but
LY> how about the initial geometry? It seems that I don't need to make
LY> the input geometry satisfy the constraint, because in the output it
LY> prints the current value and its difference with the desired value.
LY> However, the program updates the structure by thousands of times,
LY> but never gets convergence. And the constraint is not reached
LY> neither. What's the algorithm to do constraint optimization? Is this
LY> feature kind of broken, or do I miss something? Thank you very much!

geometry optimization with constraints is somewhat tricky, compared
to MD. how about, you start with an simulated annealing and then
switch over to geometry optimization when you are close to the minimum?

axel.

LY> 
LY>   Lan-Feng
LY> 
LY> ----------------------------
LY> Dr. Lan-Feng Yuan,
LY> Postdoctoral Associate,
LY> Department of Chemistry,
LY> Princeton University,
LY> Princeton, NJ 08544, USA
LY> Office Phone: 1-609-258-1834
LY> Fax: 1-609-258-6746
LY> ----------------------------
LY> _______________________________________________
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LY> 

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