Re: GU: HINT Coordinates

[wall@phys.chem.ethz.ch (Ernst U. Wallenborn)]

>Hello
>Recently we decided ti perform some calculatiuons using the MP2
>methodology. However, Gamess´s manual is not clear about this
>point. Our problem are the way to define the first two atoms.
>We did the following test, but program stops because it cannot
>read the HINT connectivity
>
>Our structure is a azetidin-2-one ring.
>Does anobody know where the problem is?
>Is ther e any way to translate from internal coordinates,
>xyz coordinates,.. to Hilderbrandt coordinates?
>And finally, is it possible to optimize transition states
>with this methodology using Gamess?
>
> $CONTRL SCFTYP=RHF MPLEVLRUNTYP=TRUDGE NZVAR$ COORD=HINT $END
[snip]

>Juan Frau
>Universitat Illes Balears
>Palma de Mallorca. Spain
>E-mail: DQUJFM0@ps.uib.es


Hi Juan,


Three things:

1)	You didn't tell us what the problem was. 'it cannot read the HINT
connectivity' is waaaay not specific enough. You should add the important
lines of the GAMESS output next time.

2)	Hilderbrandt coordinates are a fine thing if you are working on
highly symmetric systems. This one is C1, Cs at best. Why didn't you use
MOPAC or Gaussian style internals or cartesians in the first place. They
are easier to write down and less error-prone.

3)	Who on earth told you to do a geometry optimization with TRUDGE?
RUNTYP=OPTIMIZE is what you're supposed to use if possible. And with the
most recent version having MP2 gradients it definitely is possible.

So try something like:



 $CONTRL runtyp=optimize exetyp=run mplevl=2 scftyp=rhf
  COORD=CART UNITS=ANGS  
 $END
 $system timlim=1800 memory=1250000 $end
 $basis gbasis=n21 ngauss=3 $end
 $guess guess=huckel $end 
 $DATA
prova.inp
C1
N    7.0     1.03600   0.23000  -0.30900 
O    8.0     0.01900  -0.04900   1.86900 
H    1.0     1.88800  -0.27500  -0.27100 
C    6.0    -1.07600  -0.10100  -0.43900 
C    6.0    -0.02600   0.00400   0.66800 
C    6.0     0.07900   0.00100  -1.46100 
H    1.0     0.26300  -0.90400  -2.06300 
H    1.0    -1.81000   0.72000  -0.46600 
H    1.0    -1.64400  -1.04400  -0.45300 
H    1.0     0.04500   0.86600  -2.14200 
$END

this one is syntactically correct (i tested it), and should do just
what you want.


hth

Ernst-Udo Wallenborn
Laboratorium fuer Physikalische Chemie
ETH Zentrum
CH-8092 Zurich