Subject: In re CCL:G98: Massage and %Chk

From: The Matt <[email-masked]>
Date: 11 Apr 2002 15:45:30 -0600

Ladies and gentlemen, thank you for your replies about my questions with
"one-file" BSSE.

My conclusion is, while the suggestions of re-Massage-ing the Chlorine
back to 17.0 were correct in constructing a one-file calculation, this
leads to the wrong answer!  The reason is a fault in using one input
file and one .chk file.  To wit:

First Step (no ghost):
    24 basis functions       72 primitive gaussians
    20 alpha electrons       20 beta electrons

Second Step (ghost Cl):
 The nuclear charge for atom    1 has been changed to Z=  0   0.000000
 ...
    24 basis functions       72 primitive gaussians
    11 alpha electrons       11 beta electrons

Third Step (ghost CO2, turn on Cl):
 The nuclear charge for atom    1 has been changed to Z= 17  17.000000
 The nuclear charge for atom    2 has been changed to Z=  0   0.000000
 The nuclear charge for atom    3 has been changed to Z=  0   0.000000
 The nuclear charge for atom    4 has been changed to Z=  0   0.000000
...
 Warning:  center   1 has no basis functions!
...
    15 basis functions       45 primitive gaussians   <-----!!!!!
    9 alpha electrons        9 beta electrons

In using just one Checkfile, Gaussian imports *no* basis functions for
Cl into the third step, since center 1 is read as a ghost "Bq". 
Obviously, this leads to a nonsensical answer.

The right way to do this is to separate out the jobs as Mr. Cuffe
suggested:

> This solution may not appeal to you, but it should work on a unix 
> system. Run as 3 separate jobs in sequence. for the Cshell a 
> command line like the following should do the trick
> g98 job1; cp trial.chk trial1.chk; g98 job2; g98 job3;&
> Where job3 references trial1.chk and job2 references the original 
> trial.chk.

Thank you all for your prompt help, and remember, sometimes the long way
is the best way.

Sincerely,
Matt Thompson
-- 
"And isn't sanity really just a one-trick pony, anyway?  I mean,
all you get is one trick, rational thinking, but when you're good
and crazy, ooh ooh ooh, the sky's the limit!" -- The Tick
  TheMatt -- http://ucsub.colorado.edu/~thompsma/Home.html

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From: Xavier ASSFELD <[email-masked]>
Date: Fri, 12 Apr 2002 09:56:12 +0200

Hello,

I think it is possible to have only one input file
using the CHKBAS keyword.
Here follows a silly exemple:

%CHK=hene.chk
# RHF/STO-3G SCF=(DIRECT,TIGHT)

He...Ne

0  1
He
Ne 1 3.0

--LINK1--
%CHK=hene.chk
# RHF/CHKBAS SCF=(TIGHT,DIRECT) GUESS=CHECK GEOM=ALLCHECK MASSAGE

1 NUC 0.0

--LINK1--
%CHK=hene.chk
# RHF/CHKBAS SCF=(TIGHT,DIRECT) GUESS=CHECK GEOM=ALLCHECK MASSAGE

1 NUC 2.0
2 NUC 0.0

Hope this helps.
-- 

                                      ...Xav

Ast. Pr. Xavier Assfeld             [email-masked]
Laboratoire de Chimie theorique     (T) 33 3 83 91 21 49
Universite Henri Poincare           (F) 33 3 83 91 25 30
F-54506 Nancy BP 239                http://www.lctn.uhp-nancy.fr

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From: The Matt <[email-masked]>
Date: 12 Apr 2002 08:20:46 -0600

> # RHF/CHKBAS SCF=(TIGHT,DIRECT) GUESS=CHECK GEOM=ALLCHECK MASSAGE

You are quite right, it does work.  Thank you for pointing out this
option, it's new to me and useful.  It will make life easier (much fewer
files to handle).

Matt Thompson

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From: Pedro Salvador Sedano <[email-masked]>
Date: Fri, 12 Apr 2002 18:51:44 +0200

Hello,

I'd like to add that it's not a good option to use as a guess for the 
ghost orbital calculations the MO obtained in the dimer calculation, as 
at least one of the first two molecular orbitals would lay on the ghost 
functions, which is a very bad choice...

-- 
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Pedro Salvador Sedano
Ph.D. Student                             I'll stare the sundown,
Institut de Quimica Computacional         untill my eyes go blind.
Universitat de Girona                     I won't change direction,
Campus Montilivi 17071, Girona,Spain     and I won't change my mind.
iqc.udg.es/~perico
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