NMR shift calc'n in G94. Summary
Hi everybody,
recently, I posted a question regarding the calculation of NMR chemical shifts
(shieldings) in G94. I got some interesting and nice replies. Here is my
summary. Many thanks to all who replied, I certainly enjoyed hearing from you!
If anybody wants to comment further on the subject, please do so.
Originally, I asked (Fri, 10 Nov 1995)
> this is a question to the GAUSSIAN user's community.
>
> I understand that G94 can calculate NMR chemical shifts with
> the GIAO scheme. Now I would like to know whether the shift
> calculation is possible only on some levels of theory,
> and if so, on which ones. E.g., I don't think that -- say --
> Coupled Cluster methods and shift calculations are compatible
> yet in G94. In particular, I'd like to know wether G94/DFT and
> shift calculations go together or not.
>
> Any references to papers using G94 for shift calculations would be
> of interest, too.
>
> I am not a GAUSSIAN user, therefore I thought I ask the net;
> I do so out of pure curiosity. For my part, I am working on the development
> of a DFT-GIAO method for the chemical shift (shielding, to be more
> precisely). It is therefore interesting to know what other people out
> there are doing.
>
These are in fact two questions, one regarding the abilities of G94, and
one about any references. As far as the first one is concerned, this is
completely answered by the Gaussian people proper, and also by some other
users, see below (e.g., David Case and Martin Kaupp).
For the other part, my understanding is that the NMR feature (and G94 as
such!) is so new that there aren't many printed papers yet.
Here are the responses that I got:
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David A. Case writes (Fri, 10 Nov 95)
Hi George!
The G94 manual states that shielding calculations can be done for
"Hartree-Fock and pure DFT( i.e. non-hybrid ) methods." I have used
it a fair amount with HF wavefunctions [one paper in press, I can send
it to you if you like, concerns proton shieldings in aromatic ring systems.]
I tried G94 once with DFT, but got very weird results, pretty clearly
incorrect, but I have not had time to follow up on this result; it may
be a result of an error on my part. If I get time to try it again, I'll
let you know.
Good luck on your studies. I've been using the Malkins/Salahub version
of deMon for shielding calculations for bioorganic systems like peptides
and sugars. Again, mainly concentration on proton shieldings. Results
look pretty good (with big enough basis sets, etc.). Let me know if you
want more details. Might be fun to run some test molecules in parallel,
just to see how close your stuff and theirs is.
...dac
==================================================================
David A. Case | internet: case.,at,.scripps.edu
Dept. of Molecular Biology, MB1 | bitnet: case%scripps.edu.,at,.sdsc
The Scripps Research Institute | fax: 619-554-3789
10666 N. Torrey Pines Rd. | phone: 619-554-9768
La Jolla CA 92037 USA | WWW: http://scripps.edu/case
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Doug Fox (from Gaussian proper) writes (Mon Nov 13)
Georg,
Gaussian 94 can compute GIAO shielding tensors for both HF and DFT
methods. Local gauge shielding tensors and magnetic susceptibiliities
can be computed for HF and DFT using the Continuous Set of Gauge
Transformations (CSGT) or the Individual Gauge for Atoms In Molecules
(IGAIM) methods.
We are working on extensions to post-HF methods for future releases of
Gaussian.
Doug Fox
help.,at,.gaussian.com
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Renee Peloquin Mattie writes (Mon, 13 Nov 1995)
ACES II does NMR shifts based on coupled cluster calculations.
Renee Peloquin Mattie
rpmattie.,at,.omni.voicenet.com
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Martin Kaupp writes (Mon, 13 Nov 1995)
Hi Georg,
As you know, we are using the DFT(IGLO) approach of Malkin et al.,
mainly connected with deMon, but recently also with interfaces
to other programs.
As I have G94, I have also played around with its NMR features.
The NMR shift calculations are at present possible with HF and 'pure'
DFT (uncoupled KS, same as you are doing). I have actually already seen
some posters and even one paper of
people who claim to have used a hybrid DFT/HF functional, although this is
not supported in the manual. Indeed, if you use the corresponding key-words,
you get some resonably-looking results. However, it is not clear at all how
it's done, uncoupled for the KS part, coupled for the HF part ?
Also, I have seen no publication whatsoever describing G94's NMR features.
Apart from GIAOs, the program also supports some other choices of gauge
origin: CSGT (continuous set of gauge transformations), IGAIM (individual
gauge for atoms in molecules), and of course common gauge origin.
Best regards, Martin
------------------------------------------------------------------
| Dr. Martin Kaupp |
| Max-Planck-Institut fuer Festkoerperforschung, |
| Heisenbergstrasse 1, D-70569 Stuttgart, Germany, |
| Tel.: country-code+711/689-1532 |
| Fax.: country-code+711/689-1562 |
| email: kaupp.,at,.vsibm1.mpi-stuttgart.mpg.de |
| |
| and Institut fuer Theoretische Chemie, Universitaet Stuttgart, |
| Pfaffenwaldring 55, D-70569 Stuttgart, Germany |
| Tel.: country-code+711/685-4399 |
| Fax.: country-code+711/685-4442 |
------------------------------------------------------------------
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Frederic Bouyer writes (Mon, 13 Nov 1995)
Hi Georg,
Could I share with you replies you could receive?
I am highly interested in NMR spectra on molecules from ab-initio calculations.
Thank you very much in advance.
Frederic Bouyer
------------------------------------------------------------------------------
Frederic BOUYER
Laboratoire d'Electrochimie et de Chimie Analytique
E.N.S.C.P.
11, rue Pierre et Marie Curie
75231 PARIS Cedex 05-France
Tel: (33)-1-44-27-67-51/66-94 ou (33)-1-43-54-53-84
Fax: (33)-1-44-27-67-50
http://alcyone.enscp.jussieu.fr/Pages/LECA/GP/FB/
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==============================================================================
Georg Schreckenbach Tel: (Canada)-403-220 8204
Department of Chemistry FAX: (Canada)-403-289 9488
University of Calgary Email:
schrecke.,at,.zinc.chem.ucalgary.ca
2500 University Drive N.W., Calgary, Alberta, Canada, T2N 1N4
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