AMBER Archive (2004)

Subject: Re: AMBER: a question

From: David A. Case (
Date: Tue Dec 21 2004 - 16:07:51 CST

On Tue, Dec 21, 2004, Germ?n Sciaini wrote:

> I?m trying to build a rigid molecule of ammonia and I have problems when I
> try to link all H atoms and do shake. shake does not work with H-H bond...

It may be that trying to shake all 6 edges of the ammonia tetrahedron (3 NH
bonds + 3 HH bonds) leads to too many interlocking requirements. Ideally,
you would want to adapt the matrix routine setlep() [in fastst.f] to handle
the ammonia situation, but this is probably not trivial. I don't know if
there is any simpler workaround, however.

....good luck...dac
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