CCL:G: Crysallographic structure Vs optimized

From: "Mr shabbir" <shabbir,nenu.edu.cn>
Subject: CCL:G: Crysallographic structure Vs optimized
Date: Wed, 6 Aug 2008 07:52:02 -0400

 Sent to CCL by: "Mr  shabbir" [shabbir__nenu.edu.cn]
 Hello CCL users!
 I am a in some confusion want to explain it. Please If some one have an idea let
 me know also.
 I have taken a crystallographic structure and optimized it using Gaussian03 with
 C2 symmetry and b3lyp/6-31G* method. After optimization it gave me a round about
 planer structure. After this I have calculated its UV and IR spectra that is in
 good agreement with experimental values but the crystallographic structure has a
 dihedral angle 40 degree with side pyrrol rings which is not in my optimized
 structure. So can I say that my Gassphase optimized structure is reliable on the
 basis of calculated experimental values and start my futher calculations?
 Secondly I tried to freeze that dihedral angle using guessview but it could not
 freeze during optimization. How to freeze dihedral angle during optimization so
 that it will not change during calculations?
  Mr.Shabbir
 Northeast normal university Changchun
 P.R.China
 shabbir . nenu.edu.cn