Dear Andrey,

Our suggested solution would be to first try UNCONSTRAINED optimisation
in C(2) symmetry (or more generally in the largest subgroup of the full
symmetry that is currently supported by ADF). There should be a good
chance that the program finds the desired minimum of S_4 symmetry,
unless other minima of lower symmetry are closer to the starting point
(or deeper).

If the optimization in lower symmetry does not give the desired result,
it may indeed be useful to specify some additional constraints, but
be careful that constraints beyond those implied by the S_4 symmetry
may lead to artifacts because of the reduced degrees of freedom.

Best regards,
Stan van Gisbergen

======== Your mail ================

Dear ADF users,

I'd like to optimise the geometry of the molecule with S_4 symmetry which
is not available in ADF 2002.??. Is the constrained optimisation under C_2
symmetry the best solution in this case?

With the best regards,
Andrey.
 
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Dr. S.J.A. van Gisbergen SCIENTIFIC COMPUTING & MODELLING NV
Phone: +31-20-4447626 Vrije Universiteit, Theoretical Chemistry
Fax: +31-20-4447629 De Boelelaan 1083
E-mail: vangisbergen_at_scm.com 1081 HV Amsterdam, The Netherlands
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Received on 2002-11-08 15:17:16