Subject: CCL: comment on calculation of HFS constants"

From: Steven Creve <[email-masked]>
Date: Thu, 2 May 1996 14:31:24 +0100 (NFT)

On Thu, 2 May 1996, Philippe Maitre wrote:

> 
> Hi,
> 
> > Dear collegues,
> > 
> > I wish to calculate theoretical hyperfine splitting constants on the 
> > basis of ab initio calculation results (spin densities, charge densities, 
> > geometries) done for radical species. What program can do this or how can 
> > it be done?
> > Thank you!
> > 
> >
> 
> I worked on the hypervalent radical PH4 few years ago during my PhD,
> and the day of my defense I remember a question "why did not you calculate
> the HFS constants ?". The main problem is the Basis-Set since the Gaussian
> types are not adpated for such a purpose because they have the wrong shape
> at the nucleus. Slater orbitals are better (i remember some papers from the
> '70s from Norton about this point).
> 
> Let me know your comments and conclusions, I am still interested in this.
> 

Hi.

Actually, I am currently working on HFS calculations of small Phosphorus 
compounds. There is indeed a serious problem concerning the basis sets: 
the problem being, I guess, the bad cusp-description using gaussians. 
IGLO-III and cc-pVTZ perform reasonably, using QCISD. However, when using 
DFT for the calculation of this properties, the IGLO-III performs very badly.
I think - and that is the reason of my question about P-basis sets - that 
a well-balanced triple zeta basis set could cure a lot of the current 
problems.

Steven
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Steven Creve                       [email-masked]
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