Subject: CCL: SAC-CI in Gaussian03

From: Artem Masunov <amasunov[at]LANL.gov>
Date: Sun, 25 May 2003 20:44:03 -0600

Marcin,
 First, SAC ground state is not just the reference determinant, it
includes correlation corrections.
 You must specify the target state, even if you do not do any excited
states. In your case it is
TargetState(SpinState=Singlet,Symmetry=1,Root=0)
 Check your single point output, there is only one symmetry with Root=0
which is your ground state (may not be Symmetry=1, thouth).
 BTW, do not bother reading HF guess, unlike some correlated methods it is
the default reference. Instead, try using LMO=PM, you will probably get a
better total energy with localized reference.

hope this helps,
Artem
________________________________________________________
From:  <makowskm[at]chemia.uj.edu.pl>
Date:  Fri, 16 May 2003 08:59:11 +0200 (CEST)
Subject:  SAC-CI in Gaussian03

Dear CCLers,
I have a problem with using SAC-CI method included in Gaussian03 suite.
I am interested in geometry optimization of the ground state using this
method, but until now all of my tries of preparing an appropriate input
failed. My input looked like this:

%chk=/tmp1/ucmakows/benosnz_sac
#P SAC-CI(SACOnly)/cc-pVDZ opt GFinput IOP(6/7=3) Guess(Read)
Geom=AllCheck

where checkpoint file is from previous RHF optimization

It resulted in:

Must specify TargetState for gradients.
 Error termination via Lnk1e in /usr_ext1/gaussian03/g03/l923.exe at Thu
May 15
16:46:24 2003.
 Job cpu time:  0 days  0 hours 32 minutes  4.5 seconds.
 File lengths (MBytes):  RWF=   7059 Int=      0 D2E=      0 Chk=      8
Scr=   1

> From my previous experiments it looked like that TargetState option is
addressed to excited states not a ground(reference) one.

May anyone give any suggestion what the route section should be?

Thanks in advance,

--
Marcin Makowski
Ph.D. student in Theoretical Chemistry,
Jagellonian University