CCL:G: Opt with Full point group Symmetry in G09

 Sent to CCL by: "Mr Mi Yang" [agri_chemist\a/yahoo.com]
 First of all thanks for replies of Jimenez Vazquez, Cory Pye and others.
 Actually, I have used Z-matrix made by molden and it works perfect to maintain
 symmetry in G09 only
 for small molecules like benzene. But for a Fulleren like molecule to build
 Z-matrix manually is almost
 impossible.
 Is there any software which can help to build Z-matrix for 3 dimensional
 fulleren like big molecule by
 using some dummy atoms so that it can maintain symmetry in G09 opt...?
 I observed below mentioned problem in most of molecules with DnD or DnH
 symmetries where G09
 try to maintain largest Abelian group instead of full point group.
 I have not included any diffused function in basis set but will check a bigger
 set without diffused
 function.
 regards,
 Mr.MiYang
 > "Hugo Alejandro Jimenez Vazquez hjimenez],[woodward.encb.ipn.mx"
 wrote:
 >
 > Sent to CCL by: Hugo Alejandro Jimenez Vazquez
 [hjimenez,+,woodward.encb.ipn.mx]
 >
 > Although MiYang does not mention it, I would guess that he is using
 > diffuse functions in the basis set employed in his (her?) calculations.
 > I am also trying to do calculations on fullerenes, and I have found that
 > the inclusion of diffuse functions breaks the symmetry of the wavefunction
 > with respect to the symmetry of the molecule under analysis. Gaussian says
 > that "the density has only Abelian symmetry" and in an
 optimization the
 > point group of the molecule changes to that of the density with the
 > corresponding increase in computational cost. I have not found a way to
 > solve this problem other than getting rid of the diffuse functions from
 > the basis set, although I am still looking. I asked for advise from
 > Gaussian, but they could not help me. The problem is not particular to
 > Gaussian 09; previous versions of Gaussian also exhibit the same behavior.
 >
 > Another solution would be to use a larger basis set withouth the use of
 > diffuse functions. I have not tried Cory's suggestion though, but I
 > believe that the outcome would be the same.
 >
 > Regards,
 >
 >
 > --
 > ---
 > Hugo A. Jimenez Vazquez
 > hjimenez###woodward.encb.ipn.mx
 > Departamento de Quimica Organica
 > ENCB-IPN
 > Mexico
 >
 >
 >
 > On Tue, 27 Mar 2012, Cory Pye cpye : ap.smu.ca wrote:
 >
 > >
 > > Sent to CCL by: Cory Pye [cpye|,|ap.smu.ca]
 > > Hello Mi,
 > >
 > > I recommend the use of opt=z-matrix and a very carefully constructed
 z-matrix.
 > >
 > > -Cory Pye
 > >
 > > On Sun, 25 Mar 2012, Mi Yang agri_chemist%x%yahoo.com wrote:
 > >
 > > >
 > > > Sent to CCL by: "Mi  Yang" [agri_chemist++yahoo.com]
 > > > Dear CCL Colleagues,
 > > > I am desperately trying to optimized a C 40 fulleren molecules
 with D5d symmetry. But after my
 > > > several calculations with different coordinates it reduces the
 symmetry C2H in final geometry. I
 > > > checked CCL archives and used some helpful keywords like
 symm=loose and iop(2/17=xx),
 > > > iop(2/18=xx) upto 1 etc.
 > > >
 > > > Do Gaussian has ability to optimized only some systems in their
 Largest Abelian subgroup
 instead of
 > > > full point group...?
 > > > In my comparison of systems same point group is necessary so how
 can I optimized the above
 Fulleren
 > > > 40 (D5d) system in G09...?
 > > > Any comment or recommendation will be highly appreciating.....
 > > >
 > > > MiYang>
 > > >
 > >
 > >    *************    !  Dr. Cory C. Pye
 > >  *****************  !  Associate Professor
 > > ***   **    **  **  !  Theoretical and Computational Chemistry
 > > **   *  ****        !  Department of Chemistry, Saint Mary's
 University
 > > **      *  *        !  923 Robie Street, Halifax, NS B3H 3C3
 > > **      *  *        !  cpye]^[crux.stmarys.ca   http://apwww.stmarys.ca/~cpye
 > > ***     *  *    **  !  Ph: (902)-420-5654  FAX:(902)-496-8104
 > >  *****************  !
 > >    *************    !  Les Hartree-Focks (Apologies to Montreal
 Canadien Fans)
 > >
 >
 >