CCL:G: Combining Z-matrix with Cartesian coordinates in Gaussian
- From: "Guzman, Francisco" <fg58#%#njit.edu>
- Subject: CCL:G: Combining Z-matrix with Cartesian coordinates in
- Date: Wed, 20 Dec 2017 23:13:19 -0500
If you try opt=(modredundant,cartesian)
You should see the following error at the end of the output file:
Cannot AddRedundant with Cartesian or Z-matrix opts.
Error termination via Lnk1e in l1.exe
> From the description of your problem, you should be able to use
modredundant as a method of freezing a bond/angle/dihedral and relax the
rest of the structures by adding the following 1 space after your z-matrix.
*Freeze bond between atom 1 & 2:*
B 1 2 F
*Freeze angle between atom 1 , 2, & 3:*
A 1 2 3 F
*Freeze dihedral between atom 1 , 2, 3, & 4:*
D 1 2 3 4 F
This is all with Gaussian 09, Rev. C, At least for Gaussian, I do not know
of another way to freeze part of a structure and optimize without using
On Tue, Dec 19, 2017 at 10:20 AM, Grigoriy Zhurko reg_zhurko#
chemcraftprog.com <owner-chemistry(a)ccl.net> wrote:
> Sent to CCL by: Grigoriy Zhurko [reg_zhurko:chemcraftprog.com]
> > What are the errors?
> Most atoms are frozen.
> > It's also unclear what you are trying to do.
> > Are you trying to do a relaxed scan (PES), rigid scan, or just
> > optimize?
> Relaxed PES scan.
> > If it's a relaxed scan, then opt=modredundant is
> > required.
> Usually opt=modredundant implies fixing (scanning) a distance, angle or
> a dihedral, but I need to fix a distance between a real atom and a dummy
> atom between two other real atoms. I don't see how I can specify this
> constraint with modreduntant only.
> > I believe for any modredundant job Gaussian internally
> > optimizes with a z-matrix only.
> This is strange for me. I found that Z-matrices are a very bad choice for
> optimizing rings.
> > Something along the lines of forcing
> > the job to optimize using cartesian coordinates, opt=(modredudant,
> > cartersian), will not work.
> Are you sure?
> Grigoriy Zhurko.>
Otto H. York Department of Chemical, Biological and Pharmaceutical
New Jersey Institute of Technology
Email: fg58(a)njit.edu, guzman.research(a)gmail.com