[molpro-user] Saving orbitals to file and natural orbitals

[Stephen Harrison]

Dear Molpro User Group,

I wonder if I could have some advice regarding some calculation inputs
please? I'm still fairly new to the program and can't find much clear
guidance regarding these issues in the documentation.

Firstly, I understand that MOLPRO uses natural orbitals by default at
MCSCF level, after discussing this with my supervisor we seem slightly
perplexed by this. Are the MCSCF natural orbitals the same as normal MCSCF
orbitals? because as far as my understanding goes I thought the 'true'
natural orbitals only came out during the MRCI level calculation (i.e.
after MCSCF has already run).

Secondly, the documentation seems to make it clear that you can save
orbitals to file using the orbital/save command. However I tried this and
it seemed that MOLPRO didn't create these files I requested? (INPUT is
below).
I would like to take them and use them in an R-Matrix calculation so any
format information you could give me would also be really helpful. I know
it's possible to brute force it by copy and pasting orbitals from the
output, but if I could get them saved in-situ, particularly in the correct
format, it would be a great help.

Here was the INPUT I tried to use, but after I couldn't find the files
containing the orbitals.

BASIS
 default, cc-pVTZ
 END

 {RHF, ENERGY=1.e-8 ;
       OCC, 9, 2, 2, 0;
       ORBPRINT,5}

 {MCSCF
         THRESH, ENERGY=1.e-8;
         OCC, 10,3,3,0 ; CLOSED, 7,0,0,0 ; FROZEN, 0,0,0,0 ;

 WF, 25, 1, 1;
 STATE, 1;
 WEIGHT, 0.5;
 ORBITAL, 2000.1

 WF, 25, 2, 1;
 STATE, 1;
 WEIGHT, 0.25;
 ORBITAL, 2000.2

 WF, 25, 3, 1;
 STATE, 1;
 ORBITAL, 2000.3
 WEIGHT, 0.25;

         ORBPRINT,10}

 {MRCI
        THRESH, ENERGY=1.e-8;
         OCC, 10,3,3,0 ; CLOSED, 7,0,0,0 ; CORE, 0,0,0,0 ;
         STATE, 1;
 }


Thank you very much for any help, it would greatly be appreciated!
Stephen Harrison, UCL



-- 
Stephen Harrison, Msci.
stephen.harrison at ucl.ac.uk
stephen at quantemol.com

Department of Physics & Astronomy,
University College London,
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