Subject: ZINDO/S vs ZINDO-1

From: "Mills, Nancy S." <[email-masked]>
Date: Thu, 28 Jun 2001 17:53:12 -0500

I had asked if there was a difference between ZINDO/S and ZINDO-1 and which
was in Gaussian 98, which listed ZINDO-1.

Here are the primary responses:

yes, there are differences. They are mostly in atomic parameters. ZINDO/S is
for spectroscopic simulations (and the method is pretty good at it!).
ZINDO/1 is for geometry optimizations (and the method is not so good,
unfortunately...).
There was a development (see Int. J. Quantum Chemistry, vol.81, 187-201,
2001) by M.C.Zerver group in Florida to fix some problems with ZINDO/1 but I
think that the changes have been implemented only in the original ZINDO
program, not in Gaussian 98 or HyperChem.
				Regards,

Serge
________________________________________________________________

	Sergey I. Gorelsky

A bit of history:

The "1" in ZINDO-1  (originally called INDO/1) comes from the way the
one-center core integrals were obtained from ionization potentials only (as
in the original CNDO/1 model) and uses an empirical expression for the
two-center coulomb integrals.  In Mike's original paper from TCA 1973, they
developed the first spectroscopic parameterization for this approach and
applied it to benzene, pyrrole and the azines.
This method became known as the INDO1/S. Due to the popularity of
Mike's ZINDO program, over time the method simply became known as 
ZINDO/s
The INDO/1 (for geometries) approach uses somewhat different parameters and
employs analytical two-center coulomb integrals over Slater orbitals.  It
was fairly useful for geometry optimization for transition metal systems,
especially since no other popular semi-empirical approach could treat these
systems at the time.  However, for general organic systems, INDO/1 (or
ZINDO-1) gave poor results.
The ZINDO/s method has become more popular with the passing of time. This is
remarkable for a semi-empirical method first developed in the early 70's.
Mike and I used it to do some of the first calculations of the bacterial
photosynthetic reaction center; involving hundreds of quantum-mechanically
treated atoms.  At the time this calculation required a Cray supercomputer
to run.  Later, at PNNL, I used ZINDO in a QM/MM polarizable model I
developed to re-run the reaction center calculations, this time including
the entire reaction center protein in the calculation (as polarizable MM
atoms) with very good results (J. Phys. Chem. 1995, vol 99,  6374).  This
calculation ran on a fast workstation.  (now I can routinely rerun these
calculations on the pc from which I am typing this message).
Over the years, Mike was very interested in getting a single semi-empirical
Hamiltonian to work well for both geometries and spectra.  In the last 3
years, Mike, Kotker Rosch, and Alexander Voityuk did some interesting work
on NDDO-G, which was a new semi-empirical scheme meant to address this issue
(J. Phys. Chem A. 1999, vol 103, 4553).
There was never any "official" ZINDO/s parameterization that was published
with statistical analysis like the AM1 and PM3 methods.  For the first row
and first transition series the parameters were pretty much stabilized over
the years.  However, they would often be changed for a particular paper to,
for example, improve n->pi* transitions, or to improve triplet spectra.
A few years ago, I helped the Gaussian developers with some of the more
obscure ZINDO issues when they were implementing their version of ZINDO.  To
my knowledge, the Gaussian implementation and our ArgusLab implementation of
ZINDO should agree pretty well.  We are putting in a parameter editor to the
next version of ArgusLab to allow for easier modification of ZINDO
parameters and to allow new elements to be added.  I don't know how
HyperChem's results compare with Gaussian and ArgsuLab.
Hope this helps a bit.
(shameless plug...)
You can obtain ArgusLab free of charge at:
http://www.planaria-software.com <http://www.planaria-software.com> 

				Cheers,
				Mark Thompson
				Planaria Software
				Seattle, WA.

> From two readers, including one from Gaussian, confirmation that the version
of ZINDO in Gaussian 98 is ZINDO/2, even though the documentation suggests
otherwise.

Finally, a caution about use:

word of advise, be careful with zindo and anions. I am getting very funny
results with that.
Adrian E. Roitberg [mailto:[email-masked]]
<mailto:[mailto:[email-masked]]> 

Thanks to everyone for their help.

Nancy
Nancy Mills, PhD				Phone, (210) 999-7317
Professor	Fax, (210) 999-7569
Department of Chemistry	[email-masked] <mailto:[email-masked]> 
Trinity University
715 Stadium Dr.
San Antonio, TX  78212-7200