[ghemical-devel] Gamess / Toggle Patches

[Geoffrey Hutchison]

On Mar 27, 2006, at 6:45 PM, Donald Ephraim Curtis wrote:

> Tommi, i'm just curious why there is even a "max" distance included
> anyways.

It depends on the task at hand. Sometimes you want to lock a distance  
to at least X Å (or nm). Sometimes you want it to be exactly  
something, within a small tolerance. Sometimes you want to make sure  
two atoms are closer than X Å. I've had times when I've wanted all of  
these.

However, the cases where I want distance constraints, they're usually  
to be exactly X distance.

The three cases (less, greater, and equal) are more frequently useful  
with some sort of angle or torsional constraint. For example, you're  
not quite sure the non-bonded angle, but don't want it to be more  
than 180 degrees. Or you want the dihedral between two rings to be  
somewhere between 40 and 50 degrees, but will let the optimizer pick  
the best.

Flexibility is good in a molecular editor. :-)

Cheers,
-Geoff