[molpro-user] 回复: Re: UCCSD-F12 with CASSCF orbitals

[Kirk Peterson]

All:

my apologies for not being specific but as Gerald says this only works correctly in the current developers version. You will certainly get incorrect answers with the current production version. 

-Kirk

Sent from my iPhone

On Aug 10, 2011, at 4:31 PM, binjiang.nju <binjiang.nju at gmail.com> wrote:

> Dear Gerald and Kirk,
>  
> Many thanks for your reply. I finally use the procedure hf/multi/hf(maxit=1)/uccsd-f12(orbital,ignore_error), which works fine now. I'm also grateful for Gerald's alert about the ccsd energies with non-rhf orbitals. I would like to do more test to check if the ccsd energies with this strategy are correct.
>  
> Best, Bin.
> 2011-08-10
> binjiang.nju
> 发件人: Gerald Knizia <knizia at theochem.uni-stuttgart.de>
> 发送时间: 2011-08-11 05:38
> 主 题: Re: [molpro-user] UCCSD-F12 with CASSCF orbitals
> 收件人: "binjiang.nju" <binjiang.nju at gmail.com>
> 抄 送: molpro-user <molpro-user at molpro.net>
>  
>  
> 
> 
> binjiang.nju wrote: 
> > I am trying to do a uccsd(t) calculation with CASSCF orbitals in  
> > Molpro.2010.1, it will be useful when two quasi-degenerate states  
> > exist and sometimes improve the convergence, comparing to the  
> > uccsd(t)/hf strategy.  
> >   
> > It works fine when I use only normal uccsd(t) option, but it fails  
> > when I use uccsd(t)-f12 option. I have tried to change the basis set,  
> > active space, as well as the type of CASSCF orbitals (Natural,  
> > Canonical), all of these do not help. Then I find some information for  
> > such problem, but still no suitalbe answer. 
> >   
> > Gerald Knizia has mentioned that the F12 methods do request RHF  
> > reference functions, but he would try to fix this. (I cite his words  
> > in the following, hopefully he would not mind) 
>  
> I have semi-fixed this in the current development version (i.e., it is  
> there possible to use such orbitals now, but it requires some persuation  
> with rhf,maxit=1). However, this turned out to be more complicated than  
> anticipated, which is why I did not backport the changes to the  
> production version. In the current production version both CCSD-F12  
> programs will give (different) wrong energies when used with non-HF  
> orbitals. I would prefer to leave this issue open until the next Molpro  
> production version (i.e., the one from the current development version,  
> where this will work automatically), unless there is very strong  
> interest in having this feature available. 
> --  
> Gerald Knizia 
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