[molpro-user] MRCISD+Q calculations

[Kirk Peterson]

Dawid,

patience, none of us get paid for this  :^)

Not sure what you mean by restricting the MRCI to just singles and doubles.  Do you mean singles and doubles from a HF reference of 5 orbitals/10 electrons into just 5 virtuals? In Molpro you can't restrict the number of virtuals you use for correlation in the MRCI.  Could you describe more closely what you would like to do here?  

From your input I can already see one problem in that the HF can only handle high spin open shells, so you should just specify a closed-shell singlet.  If you want a CASSCF or some more general MCSCF with 5 virtuals  you need to use the multi program.

You'll also want to put a memory directive at the top of your input (just below the *** line) since the default is usually never so great.

In regards to MRCI+Q for oscillator strengths, there is no wavefunction associated with the Davidson correction, so this is not possible.  Dipole moments are always calculated by default, so no need for the gexpec directive.  For transition moments, these will always be calculated automatically when you have multiple states in the same symmetry.  If they're in different symmetries (separate MRCI calculations), then save the wavefunction in each case (e.g.,  ci;wf,80,1,0;save,4100.2)  and then invoke the ci code again as:   ci;trans,4100.2,5100.2    where 5100.2 contains the 2nd wavefunction.

Frozen core is default.

hope that gets you started,

-Kirk


On Feb 11, 2014, at 9:32 AM, Dawid das <addiw7 at googlemail.com> wrote:

> Hi,
> 
> Nobody can really help me with this?
> 
> 
> 2014-02-10 14:57 GMT+01:00 Dawid das <addiw7 at googlemail.com>:
> Dear molpro users,
> 
> I want to do MRCISD+Q excitation energy, oscillator strengths and dipole moments calculations. Let's say that I want to do it for S0--->S1 and S0---->S2 transitions. Now, I struggle with couple of things. Firstly, how do I specify that I want to have only single and double excitations in 10x10 space (that means 10 electrons in 10 orbitals- 5 doubly occupied and 5 virtual)?
> Secondly, I can't find how to calculate oscillator strengths and do the Davidson correction (Q).
> At last, I am not sure if my input (attached) will correctly calculate the dipole moments in all states.
> 
> I also want all of my core orbitals to be frozen. I did not specify it because it is default, right?
> 
> I have read this example:
> http://www.molpro.net/info/2012.1/examples/h2op_mrci_trans.com
> 
> If I understand it correctly, the user specifies two wavefunctions between which the transition moment is calculated. But I do not really understand how to read it. But I want to calculate this transition between states which will be calculated.
> 
> I hope you will understand where my problem lies :).
> 
> Thank you for any advice.
> Best wishes,
> Dawid Grabarek
> 
> 
> 
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