Subject: G94/98: How to skip SCF completely?

From: [email-masked] (Georg Schreckenbach)
Date: Wed, 6 Jan 1999 09:29:15 -0600

Dear CCL,

here is a GAUSSIAN related question: I would like to calculate some
properties (like forces or NMR) based solely on the "input guess". How
is this best done? (Or is it possible at all in GAUSSIAN?)

More specifically, I imagine to have some input MOs using the
"Guess=Read" command. I would specify a certain DFT method, say,
and then go on to calculate the desired properties.

What I have tried so far is the following.

A) specify a "non-standard route" that resembles a standard route but
contains no 500 links.
   Didn't work because the subsequent links requested some files that
had not been written. Perhaps one can do this in a more clever way?

B) Specify "SCF(MaxCycle=1)" as well as the appropriate flags to
avoid the error termintation due to incomletely converged SCF. These
flags are IOp(8/7=1,5/13=1).
   This procedure comes close to what I want, in particular if I use
SCF=QC. However, the one SCF cycle is still too much because it does
modify the input MOs as is clearly visible from the output. Hence, I would
want to avoid it!

Any comments or suggestions? -- I will summarize as usual.

Thank you very much!

Georg
--
Dr. Georg Schreckenbach           Tel:     (USA)-505-667 7605
Theoretical Chemistry T-12        FAX:     (USA)-505-665 3909
M.S. B268, Los Alamos National      E-mail:  [email-masked]
Laboratory, Los Alamos, New Mexico, 87545, USA
Internet:    http://www.t12.lanl.gov/~schrecke/

--
==============================================================
Dr. Georg Schreckenbach           Tel:     (USA)-505-667 7605
Theoretical Chemistry T-12        FAX:     (USA)-505-665 3909
M.S. B268, Los Alamos National      E-mail:  [email-masked]
Laboratory, Los Alamos, New Mexico, 87545, USA
Internet:    http://www.t12.lanl.gov/~schrecke/
==============================================================