Molcas Forum

gonzalezcr

Member

Registered: 2020-05-14

Posts: 4

Where is the Density from CASPT2?

Hello,

First, I must confess I am a new user/developer of OpenMolcas.
OK, I want to extract the CASPT2 density from a calculation. According to the manual it requires me to add the DENSity keyword.
Great, I did it, the question now is where is it saved? is it in the RunFile? I had enabled HDF5 but don't see any .h5 file related to CASPT2, I only see the Rasscf.h5 from a previous job (same runfile).

If it is in the RunFile, I have a second problem, I haven't manage to compile the Tools/rf2asc.f file, could you please help me with it? The readme file is not very instructive, as I don't know what are some of the variables inside the Makefile example, like GALIB, GAINC.

Finally, is the density in the AO or MO basis? (I only need the one-electron density).

Thank you in advance for your help,

Cristina

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: Where is the Density from CASPT2?

The DENSity keyword does not mean, as far as I know, you get the density, but that when the density is computed, it will the full one from the 1st-order wfn, instead of the approximate one. However, there are indications that adding the keyword may produce wrong results (even for the energies!) I wouldn't trust it without testing.

To get the density, you need to request PROPerties, then it will be saved in the .h5 file (in MO basis, I believe). However, the .h5 file is only generated if you start from an .h5 file (the "INPORB" file can be a rasscf.h5, or you can use the undocumented FILE keyword to specify a starting rasscf.h5). Otherwise, you can always reconstruct the density matrix from the natural orbitals, that you get (with PROPerties) in the Pt2Orb files.

To compile rf2asc, it should be enough enabling TOOLS with cmake (-D TOOLS=ON), you should get it in the Tools subdirectory in the build directory.

gonzalezcr

Member

Registered: 2020-05-14

Posts: 4

Re: Where is the Density from CASPT2?

Hola Ignacio,

Thank you for the quick reply, it was very instructive and useful.
Sorry to insist, but is there a way to confirm that the density is saved in the .h5  in MO basis? in the manual or in the code?

Thanks again!

Cristina

P.S. I'd be bothering you for merge/pull request soon.

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: Where is the Density from CASPT2?

Don't look in the manual for this. If the code doesn't help, the best would be to compare with what you get from Pt2Orb, or pretend it's in MO basis and compute natural orbitals... if you get something sensible, it was probably right. Or just inspect it, it should be relatively close to the RASSCF DM in MO or AO basis. As far as I remember, that's what I did with Pegamoid, and the orbitals look quite reasonable.

gonzalezcr

Member

Registered: 2020-05-14

Posts: 4

Re: Where is the Density from CASPT2?

Alright, thanks again.