Subject: Re: CCL:DNP in DMol <--> 6-31G** in Gaussian?

From: Damian Gregory Allis <damian(at)somewhereville.com>
Date: Mon, 19 Apr 2004 11:45:52 -0400

Greetings, Nicolas

	I've had quite a bit of experience using DMol3 (at NCSA) and GGA 
functionals for calculating inelastic neutron scattering spectra and 
examining the deformation of rigid molecules in the solid-state, which 
also means doing side-by-side DMol3 and Gaussian/GAMESS comparisons of 
isolated molecules for structural comparisons.

	Generally speaking, dnp and 6-31G** (as reported in the Delley papers 
as well) line up the best from among all available choices.  That said, 
I've not had an experience yet where the DMol3 geometries were closer 
to crystallographic distances than the Gaussian/GAMESS jobs.  The 
standard molecular treatments of the "familiar" atom-centered QC 
packages simply do a better job of getting the structure right in the 7 
or so systems I've worked on, so be less concerned with the DMol v.s. 
Gaussian/GAMESS structures and more concerned with those same 
comparisons to any structural data you have.  The DMol3 normal mode 
calculations, however, do a phenomenal job of reproducing the 
vibrational spectra and intensities in the INS work despite having 
slightly worse geometries.
For a useful geometry comparison, I direct you to the pagodane paper 
below.  The BH4 paper below is biased towards frequencies only but 
provides another useful comparison.  Unfortunately, I've not played 
around much with the LDA functionals, so can't provide any useful info 
about differences you'll see there.

Allis D.G., Prinzbach H., and Hudson B.S. "Inelastic Neutron Scattering 
Spectra of Pagodane: Experiment and DFT Calculations." Chemical Physics 
Letters, 386 (2004) 356-363.

Allis D.G. and Hudson B.S. "Inelastic Neutron Scattering Spectra of 
NaBH4 and KBH4: Reproduction of Anion Mode Shifts via Periodic DFT." 
Chemical Physics Letters, 385 (2004) 166-172.

cheers,
Damian

On Apr 19, 2004, at 9:28 AM, Nicolas Saettel wrote:

>  Hi all,
>  I would like to reproduce LDA calculations that were done using the 
> double numerical basis set with polarization functions in DMol (DNP). 
> Am I correct in using SVWN/6-31G** in Gaussian?
>  Thank you in advance
>  Nicolas Saettel
>
>
> -- 
>  Nicolas Saettel, Ph.D. http://nicolas.saettel.free.fr
>  Laboratoire de Chimie des Interactions Moliculaires
>  CNRS UPR 285 - Collhge de France
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> Marcelin Berthelot - 75005 PARIS
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>
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p.s. Damian apologizes for the delay.

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