CCL: Gaussian - partial optimization



 Sent to CCL by: Joslyn Y Kravitz [jyudenfr[]umich.edu]
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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?