| From: |
FRENKING%DMRHRZ11.BITNET -x- at -x- vm.gmd.de |
| Date: |
Fri, 30 Oct 92 08:49:40 CET |
| Subject: |
ECPs and 2nd derivatives again |
> From: B_DUKE -8 at 8- DARWIN.NTU.EDU.AU (Brian Duke)
> Subject: ECPs and the GAUSSIAN LAN* basis sets.
> To: CHEMISTRY (+ at +) ccl.net
> Sender: chemistry-request <-at-> ccl.net
> Mike Frisch has given us some most useful information about the
> LAN basis sets. I have two other questions that people on the list may
> be able to answer:-
> What is the best way to add polarisation d functions to the LAN* basis
> sets?
> Is this necessary and under what circumstances?
> Thanks (and Jan - keep up the good work. We appreciate it "Down under")
> Brian Salter-Duke (Brian Duke)
> School of Chemistry and Earth Sciences, Northern Territory University
> GPO Box 40146, Casuarina, NT 0811, Australia.
> Phone 089-466702 FAX 089-410460 E-mail B_DUKE "at@at" DARWIN.NTU.EDU.AU
The easiest way to manipulate a basis set, e.g. to add a
polarisation function in the GAUSSIAN series of program, is to
use the GFINPUT command which prints the current input so that
you can change it and then resubmit it in a suitable way as
general input (GEN in the key word line). Further explanations
are given in the GAUSSIAN manual under "Commands for manipulating
basis sets".
d type polarization functions for ECPs of main group
elements are as necessary as they are for all-electron basis
sets. You will find an example in our recent paper on halogen
azides (halogen = fluorine uo to iodine) where we compare the
results of geometry optimizations (i) using ECP with and without
polarization functions (LANL1DZ and LANL1DZ+P) at the HF level,
(ii) using MP2/LANL1DZ+P, and (iii) all-electron basis sets at
the HF and MP2 level. The exponents for the d-type polarization
functions were taken from Huzinaga, i.e. they are the same as for
all electron basis sets. The paper is in Inorg. Chem. 31 (1992)
3647.
We have also tested the importance of adding polarization
functions for transition metals, i.e. f-type functions. There is
a paper in print by us on CrF6 which shows a dramatic influence
of including f functions on Cr on the relative energy of the Oh
and D3h form. Thanks are due to Colin Marsden (down under!!) for
pointing this out to us. At the HF level it makes a difference of
12 kcal/mol!! So f type functions may be very important for TM
compounds. Because of this, we started a project optimizing
exponents for f type functions of all TM elements for the ECP
basis set of Hay and Wadt, but with the contraction scheme
(441/2111/41). (This is for the first row, the second and third
rows differ by the number of d functions and have contraction
schemes (441/2111/31) and (441/2111/21), respectively). The
exponents are obtained for CISD wave functions. The project is
nearly finished and it should be done in the next couple of days
(each student has one triade of TM elements, the student who is
the last pays for a round of good german beer.... - it will be
done very soon!!). Anyone interested should send me a fax number
and I will send him the exponents.
++++++++++++++++++++++++++++++++++++++++
Gernot Frenking, Prof.
FB Chemie, Universitaet Marburg
Hans-Meerwein-Strasse
D-3550 Marburg
Germany
Tel.(06421)285563
frenking (+ at +) dmrhrz11.bitnet
++++++++++++++++++++++++++++++++++++++++
Brian:
We never used INDO or other semiempirical methods, so I do
not have any parameters for Mo or other elements. Why not using
the ECP?
Best wishes,
Gernot Frenking
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