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