CCL:G: MOPAC/MOZYME PBC calculations

["Andrew Yeung" <andrew.yeung _ mail.chem.tamu.edu>]

 Sent to CCL by: "Andrew Yeung" [andrew.yeung%x%mail.chem.tamu.edu]
Thanks for getting back. I'll use the .arc files to generate new MOPAC
 input files. I suppose that MOPAC calculations are so fast that
 reading in force constants is not a huge advantage.
I've turned to MOPAC because it is able to perform PBC calculations
 using semi-empirical hamiltonians, whereas Gaussian 09 is only able to
 use HF & DFT. Furthermore, G09 does not report enthalpies with a
 frequency calculation (and that must be done numerically).
 On Sun, 26 Aug 2012 12:12:48 -0400
  "John McKelvey jmmckel::gmail.com" <owner-chemistry{}ccl.net>
 wrote:
>  Sent to CCL by: John McKelvey [jmmckel]-[gmail.com]
> Have you tried the latest version of Gaussian for all this as I
>  think
>  it also contains one of the latest MOPAC versions?
> In MOPAC itself you can use the DENOUT keyword to keep a
>  satisfactory
>  current density and then  OLDENS to read YOUR_FILENAME.DEN in to
>  start
>  a subsequent job.
>  You can carve out an input geometry from an archive file
>  (YOUR_FILENAME.ARC).  To the best of my knowledge MOPAC does not
>  output intermediate geometries, and I am not aware that it outputs a
>  Hessian that can be read back in.
> Again,  Gaussian included version of MOPAC can likely do all you
>  want.
>  John McKelvey
>  On Fri, Aug 24, 2012 at 6:27 PM, Andrew Yeung
>  andrew.yeung=-=chem.tamu.edu <owner-chemistry%x%ccl.net> wrote:
> >  Sent to CCL by: Andrew Yeung [andrew.yeung^^chem.tamu.edu]
> >  Hi all
> > I am doing a few PBC calculations on MOPAC, and I was hoping for
> >  some
> >  advise.
> > Since the system is rather large (and I suppose the initial guess is
> >  poor),
> >  I cannot get SCF convergence unless I use the MOZYME keyword. The
> >  online
> >  manual (http://openmopac.net/manual/mozyme.html) gives some tips on
> > multi-step jobs (MOZYME for geometry optimization, then MOPAC, then
> >  perhaps
> >  FORCE).
> > Since my jobs have started already (MOZYME then FORCE), I want to
> >  let it
> >  run, and do the MOPAC equivalent of "geom=allcheck guess=read
> >  opt(readfc)"
> >  on the resultant output file(s). Is this possible? How else can I
> >  start a
> >  new calculation based on an old one? Should I edit the archive
> >  (.arc) file
> >  into a new MOPAC input file?
> >  Thanks for your comments.
> >  --
> >  Andrew Yeung
> >  Donald J. Darensbourg Research Group
> >  Department of Chemistry, Texas A&M University
> >  3255 TAMU
> >  College Station, TX 77843-3255
> >  Tel: 979 845 4837
> > Fax: 979 845
> >  0158http://www.ccl.net/chemistry/sub_unsub.shtmlConferences:
> >  http://server.ccl.net/chemistry/announcements/conferences/>;
>  --
>  John McKelvey
>  10819 Middleford Pl
>  Ft Wayne, IN 46818
>  260-489-2160
>  jmmckel%x%gmail.com
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