[molpro-user] Forcing occupation numbers for HF initial guess

[Peterson, Kirk]

Dear Nike,

it seems to work fine for me with 2015.1 using a bit more conventional input:

 angstrom
 geometry={Li1;Li2,Li1,3.065}
 basis = cc-pVDZ
 {rhf;occ,3,0,0,0,1,0,0,0
 closed,1,0,0,0,1,0,0,0
 wf,6,1,2
 }

yielding:

 Final alpha occupancy:   3   0   0   0   1   0   0   0
 Final beta  occupancy:   1   0   0   0   1   0   0   0

 !RHF STATE 1.1 Energy                -14.821433808831


best,

-Kirk

> On Dec 20, 2016, at 7:36 PM, Nike Dattani <dattani.nike at gmail.com> wrote:
> 
> Greetings!
> I am using MOLPRO 2012 and would like to have ROHF for Li2 with the following:
> 
> alpha occupancy:  3   0   0   0   1   0   0   0
> beta  occupancy:   1   0   0   0   1   0   0   0
> 
> But even if I have:
> occ,3,0,0,0,1,0,0,0
> 
> The ROHF program prints:
> "Orbital guess generated from atomic densities. Full valence occupancy:
>  2   0   0   0   2   0   0   0
> 
> Initial alpha occupancy:  2   0   0   0   2   0   0   0
> Initial beta  occupancy:   1   0   0   0   1   0   0   0",
> 
> and the SCF converges to this (incorrect) solution.
> 
> I was not able to fix this by using "sym 1" in the wf card, and/or
> by adding  "closed,1,0,0,0,1,0,0,0".
> 
> Said another way, the input file:
> ========
> geometry={angstrom;Li1;Li2,Li1,3.065}
> basis = cc-pVDZ
> wf,charge=0,spin=2,sym=1
> occ,   3,0,0,0,1,0,0,0
> closed,1,0,0,0,1,0,0,0 
> core
> rhf
> ========
> gives an ROHF occupancy with sym=5 and:
> alpha occupancy:  2   0   0   0   2   0   0   0
> beta  occupancy:   1   0   0   0   1   0   0   0
> 
> regardless of whether or not I have "sym=1" and/or the "closed" card specified as above.
> 
> What can I do to force the correct initial guess to have the occupancies I want? 
> 
> Respectfully yours,
> Nike Dattani
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