Subject: G03 & AMBER - Summary

From: Jamie Platts <Platts|at|Cardiff.ac.uk>
Date: Tue, 15 Jul 2003 16:14:08 +0100 (BST)

Hi All - last week I posted a question, and now summarise the answers
I received. My sincere thanks to all who replied. Cheers, Jamie.

**Original question**
Hi there - I'm having trouble getting an ONIOM job on a platinum complex
to run in Gaussian03. Despite requesting AMBER for the outer region and
LanL2DZ for the metal core, the job crashes because there is no VSTO-3G
basis set for Pt (G98 just printed a warning and carried on).
Does anyone know of a way to avoid this? More fundamentally, why does an
AMBER calculation require an STO-3G basis anyway?

 ONIOM: restoring gridpoint  3 on chk file.
 ONIOM: generating point  3 -- low level on real system.
 Standard basis: VSTO-3G* (5D, 7F)
 IA out of range in STO.
 Error termination via Lnk1e in /usr/local/testsoft/g03/l301.exe

**From ferre|at|unisi.it Tue Jul 15 16:02:38 2003
>> This works if you realise that 3-21G is not defined for 3rd row TM's.
>> So swapping 3/5=2 for 3/5=6 (LanL2DZ) seems ok. Jamie
Actually, even for MM calculations, gaussian has to pass through the
link 301 where basis functions are attributed (it initializes other
things ...) Anyway, these basis functions for MM have no sense and are
not used in the following of the calculation.
What you have to do is to use a non standard route:
1) Save the route that comes at the beginning of the output file. This
is the thing that lists all iop, should begin with:
1/30=1,38=1,52=2,56=1/1;
....
2) In a new input file, write:
# NONSTD
Copy all the previous route
3) Replace every occurence of
3/5=2 .../1;
with
3/5=5 .../1;
where ... represents all other iops.
Actually this replace the default V-STO3G with 3-21G (for which Pt is
defined) thus the calculation should go on.

**From gaussian.com!csd|at|gaussian.com Tue Jul 15 16:10:48 2003
Unfortunately we fixed that hole.  In G98 it might have been possible
to trick it into taking a basis set at this point but in G03 it knows
that it has a built-in basis for mechanics and skips looking for basis
sets on these calculations.

**From tapaskar|at|cc.usu.ed Tue Jul 15 16:02:24 2003
Hi, I got the same problem with Os.
Gaussian people informed me that it will be taken care in the revised
version.
You may try with IOP(3/12=1)option.
Tapas

**From yubofan|at|mail.chem.tamu.edu Tue Jul 15 16:02:27 2003
You'd better change AMBER into UFF because AMBER cannot handle Pt. Good
luck.

**From m.a.zwijnenburg|at|tnw.tudelft.nl Tue Jul 15 16:02:31 2003
It's quite some time since I worked with Oniom but as far as I remember
lower level calculations are performed for both the outer region and the
whole cluster (thus including the region you want to treat at high level).
As far as I know this is needed for the substraction scheme that ONIOM
actually is. The lower level method should thus, I guess, also be able to
describe the centre region and this might be a problem with Pt and Amber. To
be sure, check the original paper.

----------------------------------------------------------
  Jamie Platts
  Dept. of Chemistry  		Phone: +44 (0) 2920 874950
  Cardiff University 	 	Email: platts|at|cf.ac.uk
  P.O. Box 912 			FAX:   +44 (0) 2920 874030
  Cardiff CF10 3TB 		www.cf.ac.uk/chemy