CCL:G: Optmizing adduct complex

From: "N Venkataramanan S" <venkataramananns{:}gmail.com>
Subject: CCL:G: Optmizing adduct complex
Date: Thu, 20 Dec 2007 23:40:05 -0500

 Sent to CCL by: "N Venkataramanan S" [venkataramananns],[gmail.com]
 Dear CCL users
 I am trying to optmize a structure involving a adduct like reactant complex (Fe
 (OXO) complex + Organic substrate). When i try to optimize the system  with opt
 keyword the organic substrate keeps on moving from initial distance of 2.5 to 13
 amstrong distance without converging(even after 75 opt cycles). When using
 opt=(TS) the same problem occurs. In liteature, I saw some reports on similar
 systems that the distance between the oxo and hydrogen of the substrates were
 about 2 to 2.5. I am using Gaussain G03
 (references : J. Phys. Chem. C 2007, 111, 12397-12406, J. Am. Chem. Soc. 2006,
 128, 8590-8606)
 Please suggest me some method to solve the problem.
 With thanks in advance
 Sincerely
 Venkataramanan