CCL: Gaussian - partial optimization

[Joslyn Y Kravitz <jyudenfr[]umich.edu>]

 Sent to CCL by: Joslyn Y Kravitz [jyudenfr[]umich.edu]
 --Replace strange characters with the "at" sign to recover email
 address--.
You should define your coordinates using internal rather than
 cartesian
 coordinates. If you define the distance between the molecules as one of
 the bond lengths then you can freeze that bond length and the two
 molecules should stay put. In fact, you can freeze all coordinates
 except
 for the atoms in the hydroxyl groups.
 Joslyn Kravitz
 On Mon, 19 Sep 2005, CCL wrote:
>  Hi,
>  I'm trying to establish a mutual orientation of two hydroxyl groups in
>  a dimeric system  (Gaussian).
>  Unfortunately, when I perform a partial optimization of these groups the
>  relative distance beetwen two molecules is also changing.
>  What could be done to optimize only hydroxyls while keeping the rest of
>  the system in its initial coordinates?