difficulty with open-shell molecule/Chen

molpro-support at tc.bham.ac.uk molpro-support at tc.bham.ac.uk
Thu Jan 6 09:25:46 GMT 2000

On Date: Wed, 22 Dec 1999 18:03:20 +0100 (CET) Chen Yu <cheny at mailer.uni-marburg.de> wrote:

> Dear Sir:
> Could you help me to solve my problem in using Molpro Program?
> I have difficulty to define the orbital of open-shell molecule with
> Molpro96.4. Must one define the electrons with alpha spin and beta spin
> seperatedly in the case of UHF? Here is my example:
> ==================================================================
>  Orbital Symmetries:
>    Alpha Orbitals:
>        Occupied  (A') (A") (A') (A') (A") (A') (A') (A') (A') (A")
>                  (A') (A") (A') (A') (A') (A") (A') (A') (A') (A")
>                  (A') (A") (A') (A") (A') (A") (A') (A') (A") (A")
>                  (A') (A') (A') (A")
>    Beta Orbitals:
>        Occupied  (A') (A") (A') (A') (A") (A') (A') (A") (A') (A')
>                  (A') (A") (A') (A') (A') (A") (A') (A') (A") (A')
>                  (A") (A') (A") (A') (A') (A") (A") (A') (A') (A")
>                  (A')   
> ==================================================================
> I know that the total alpha orbitals are 22 A' and 12 A"
> The total alpha orbitals are 20 A' and 11 A"
> And then I type the input as below:
> ==================================================================
> uhf-scf;         ! UHF calculation
> wf,65,2,3;       ! the state is 4A" (in Cs sym.)
> occ,22,12;       ! or occ,22,12,,20,11 ????
> closed,20,11;    ! or closed,20,11,,20,11 ????
> open,2.1,1.2;    ! two electrons are in A' and one electron is in A"
> maxit,200;
> uccsd(t);
> maxiter,100;
> core,4,2;        ! core electron of 4A' and 2A" are not included ..
> ==================================================================
> Is it correct or not?
> The SCF doesn't converge. With other programs such as Gaussian and 
> ACES it has no problem to converge for same basis set. So I guess 
> something is wrong with my input. Because Molpro is 
> more faster than others I would like to do my all CCSD(T) calculations 
> only with Molpro. Could you give me some ideas for this situation?
> Secondly, if it is in C1 symmetry, is it correct to input
> ===========
> wf,65,1,3;
> ...
> core,6;
> ===========
> ?
> If it is necessary I could send you a full infut file. But I prefer 
> that it is wrong only with understanding of manual about the input file.
> Thank you very much for your help. Merry Christmas!
> Yu Chen

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