CCL:G: Potential energy scans on Gaussian - Possible From Initial Geometry?

From: "Jeffrey Mo" <jdmo a mit.edu>
Subject: CCL:G: Potential energy scans on Gaussian - Possible From Initial Geometry?
Date: Fri, 3 Sep 2010 22:29:00 -0400

 Sent to CCL by: "Jeffrey  Mo" [jdmo]=[mit.edu]
 Hi everyone,
  My first post!  Hopefully I'll get some help from you guys and be able to give
 some help in the future too.
  I'm trying to perform a potential energy scan (PES) on short-chain
 alkyl/alkenyl radical transition states right now, and am running into a
 problem.  Gaussian starts each new optimization in the scan from the previous
 geometry; therefore, when I get all the way around (360 degrees) a dihedral, for
 instance, I often don't end up at the same geometry.
  Is there a way that I can ask Gaussian to perform each new optimization from
 the initial geometry?  That is, let's say we're on scan job #19 of a 36-point
 dihedral scan (where each scan increments by 10 degrees) -- then, I just want to
 change the relevant dihedral by 180 degrees from the initial geometry, not by 10
 degrees from the geometry of scan job #18.  Thanks in advance!
 Jeffrey Mo
 MIT Chemical Engineering
 Doctoral Candidate
 jdmo(a)mit.edu