[CPMD-list] how to do constraint optimization?

[Lan-Feng Yuan (lyuan@Princeton.EDU)]

  Dear CPMD users,

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

  Lan-Feng

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