Subject: SUMMARY : making ECP's

From: Patrick Bultinck <[email-masked]>
Date: Wed, 28 Sep 1994 08:35:25 +0100 (MET)

Netters,

Last week I posted a question on how to make ECP's. A small number of 
people asked for a summary, so here it is. The number of people who 
reacted, however, is even smaller !

Thanks to the people who helped me !

				ORIGINAL MESSAGE

Dear Netters,

I would like to know if there are programs that would allow me to make 
ECP's (Effective Core Potentials) (relativistic as well as 
non-relativistic) for alkaline and alkaline-earth metal IONS.

Please if you know of such programs let me know, alternatively 
references to articles which give results on ECP's for the requested ions 
are also gladly accepted !

As always, if there is enough interest, I will post a summary !

Thank you very much,

Patrick Bultinck, University of Ghent (Belgium)

				ANSWERS

Hi,

	Some references to ECPs include the following.

The first are the compact effective potential derived according to the scheme
of Walt Stevens et al.  I think the latter paper describes the s-block metals
and may even include some account of core polarization (which has been
suggested as important in reproducing things such as the structure of alkaline
earth metals).

12.	a) "Compact effective potentials and efficient, shared-exponent basis
sets for the first- and second-row atoms;" Stevens, W. J.; Basch, H.; Krauss,
M. J. Chem. Phys. 1984, 81, 6026.
	b) "Relativistic compact effective potentials and efficient,
shared-exponent basis sets for the third-, fourth-, and fifth-row atoms"Krauss,
M.; Stevens, W. J.; Basch, H.; Jasien, P. G. Can. J. Chem. 1992, 70, 612.

The Hay-Wadt scheme is described in these papers.

17.	"Ab Initio effective core potentials for
molecular calculations;" Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 270,
284, 299.

Another group which has focused considerably on ECPs are Ross, Pitzer, Ermler
and co-workers.  The following are for f-block metals, but there should be a
ref. to their earlier work since these researchers have developed their ECP
scheme for the entire Periodic Table.

	b) "Ab initio relativistic effective potentials with spin-orbit
operators. V. Ce through Lu;" Ross, R. B.; Gayen, S.; Ermler, W. C. J. Chem.
Phys. 1994, 100, 8145.

	b) "Ab Initio Relativistic Effective Potentials with Spin-Orbit
Operators.  VI.  Fr through Pu;" Ross, R. B.; Ermler, W. C.; Chistiansen, P. A.
Intern. J. Quantum Chem. 1991, 40, 829.

	I do not have any handy refs. to the work of Barthelat and co-workers.

Hope this is of some help.

Tom

+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===
		Thomas R. Cundari                         
		Asst. Professor of Chemistry               
		Computational Inorganic Chemistry Lab     
		University of Memphis                     
		Memphis, TN 38152                         
		phone: 901-678-2629                       
		fax:   901-678-3447                        
		e-mail: [email-masked]       
		http://www.memst.edu/chemistry/umchem.html
+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===+===

> Dear Netters,
> 
> I would like to know if there are programs that would allow me to make 
> ECP's (Effective Core Potentials) (relativistic as well as 
> non-relativistic) for alkaline and alkaline-earth metal IONS.
> 
> Please if you know of such programs let me know, alternatively 
> references to articles which give results on ECP's for the requested ions 
> are also gladly accepted !
> 
> As always, if there is enough interest, I will post a summary !
> 
> Thank you very much,
> 
> Patrick Bultinck, University of Ghent (Belgium)
> 
I'm afraid you will not find any public domain programs to fit ECPs. Each of
the groups involved in the development of ECPs normally has their own codes,
and it requires quite a bit of know-how to use them. So normally they don't
give it away. By the way, what do you mean with ions? Any good ECP that works
for the atoms will work for the ions as well.

During my thesis in Erlangen (with Paul Schleyer) I cooperated with my former
research group in Stuttgart (Hermann Stoll) to make quasirelativistic and
nonrelativistic ECPs for Ca, Sr, Ba. The ECPs, valence basis sets, 
testing, and first applications (to MH2) for Ca, Sr, and Ba 
have been published in J.Chem.Phys. 1991,94,1360. Note that the first
and third s-contraction coefficients for Ba should read -5.928895 and 
-0.551437, respectively (there is a typo in the paper).

The ECPs are of the energy-adjusted type of the Stuttgart group
(cf. e.g. Dolg et al. J.Chem.Phys. 1987, 86, 866, and
Andrae et al. Theor.Chim.Acta 1990,77,123 for the corresponding ECPs for
other transition metals). There was a posting some time ago, on which I
already answered and gave some hints on the required core sizes and basis sets.
You should be able to find fit in the CCL archives. Unpublished 9-valence-electron
ECPs for K, Rb and Cs are also available from the Stuttgart group
(I emphasize these small-core ECPs, as you would need core-polarization potentials
to get good results out of 1-valence electron ECPs for these atoms).
You could contact Prof. Stoll in Stuttgart 
( [email-masked] ) about the parameters.

Successful applications of the alkaline earth 10-valence-electron
ECPs may be found in:
JACS,1991,113,5606;JACS,1992,114,491;JACS,1992,114,8202;JACS,1992,114,10880;
J.Phys.Chem.,1992,96,7316;J.Phys.Chem.,1992,96,9801;JACS,1993,115,11202

Best regards, Martin Kaupp

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That's all folks !