Hi Richard, The constraints may not be exact because the optimizer will slowly apply them. There's also a penalty function for "breaking" constraint -- depending on the energetics of the system, you might get slightly "off" values.
If you need the *exact* angles and distances, you can do that through the Bond and Angle property windows. Go to View->Properties->Bond Properties. You can click on the distances and type a number to edit the distance. Same thing goes for View->Properties->Angle Properties for angles. Hope that helps, -Geoff On Dec 7, 2012, at 7:33 PM, Richard Overstreet <[email protected]> wrote: > To anyone who can help, > > I have been trying to apply constraints, angles and bond distances from a > neutron diffraction study, to a simple ammonia borane molecule (NH3BH3). I > apply constraints by going to: (extensions->molecular mechanics->constraints) > which opens the constraints table. After inputting the constraint parameters > the structure will not update and herein lies the problem. I want to be able > to export an Nwchem file with the exact applied constraints. If I preform a > simple optimization in Avogadro, before exporting to nwchem, the constraints > are used, but the bond angles and distances are not the exact parameters I > require. Is there a why to render or apply the exact constraints before > exporting? I've attached the file I'm trying to constrain as well as a png > image of the constraints used. Any help would be greatly appreciated. > > -Richard > > P.S. My system specs are as follows: > Ubuntu 11.10 x64 > Avogadro version 1.0.3 (installed with apt-get) > Library version 1.0.3 > Openbabel version 2.3.0 > Qt version 4.7.3 > <12042012NH3BH3.xyz><Screenshot at 2012-12-06 > 16:56:10.png>------------------------------------------------------------------------------ > LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial > Remotely access PCs and mobile devices and provide instant support > Improve your efficiency, and focus on delivering more value-add services > Discover what IT Professionals Know. Rescue delivers > http://p.sf.net/sfu/logmein_12329d2d_______________________________________________ > Avogadro-Discuss mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/avogadro-discuss ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Avogadro-Discuss mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/avogadro-discuss
