[molpro-user] cp-corr. Potential DF-LCCSD(T0), numerical accuracy

[Grant Hill]

Hi Raphael,

The first, and probably best, piece of advice I can give you is to  
carefully read section 29.9 of the user's manual. Pay particular  
attention to ensuring that your domains remain consistent throughout  
the scan, which probably suggests freezing your domains (at large  
separation if you wish to minimise BSSE), ensuring they are correctly  
localised etc.

Hope this helps,

Grant


On 20 Jan 2009, at 07:53, Berger Raphael wrote:

> Dear Readers,
>
> when trying to calculate a cp-corrected potential curve
> in a close region around a uncorrected minimum
> it seems to give a "noisy" curve for the dE_cp using
> only the default settings. The cp-correction at the
> equlibrium geometry is about 8*10^-4 au.
> The level is DF-LCCSD(T0)/SARC-TZVPP with DKH3
> integrals.
>
> I saw in the manual that the BSSE examples use
> {hf;accu,16}. My question is, what other non-default settings
> could be important to get a smooth cp corrected potential
> curve for this method?
> My input is basically:
>
> geometry={Au1;H2,Au1,rAuH;Au3,H2,rAuH,Au1,wAuHAu(i);
> }
> rAuH=1.6900 angstrom
> wAuHAu=[100.7,100.9,100.4,100.6,100.8,101.0]
> set,charge=1
> basis={
> ...
> }
> gdirect
> do i=1,#wAuHAu
> dkroll=1
> dkho=3
> hf
> {df-lccsd(t0),df_basis=orcadf;}
> e_tot(i)=energy
> text cp calc AuH fragment
> dummy,Au3
> set,charge=0
> dkroll=1
> dkho=3
>
> hf
> {df-lccsd(t0),df_basis=orcadf;}
> e_AuH(i)=energy
> text cp calc Au+ fragment
> dummy,Au1,H2
> set,charge=1
> dkroll=1
> dkho=3
> hf
> {df-lccsd(t0),df_basis=orcadf;}
> e_Au_plus(i)=energy
>
> e_corr(i)=e_tot(i)-e_AuH(i)-e_Au_plus(i)
> enddo
>
>
>
> (I use molpro 2008.1_mpp Linux x86_64)
>
>
> Thank You for reading
> 	Raphael Berger
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