Plugin FCIDUMP for CheMPS2

Dear loriab,

I have one question. I have installed chemps2 and psi4conda separately.
I would like to generate a matrix element for chemps2 using psi4conda.
In the psi4conda I have the following directories.
bin/ compiler_compat/ condabin/ conda-meta/ envs/ etc/ include/ lib/ share/ shell/ ssl/ x86_64-conda_cos6-linux-gnu/.

But I am unable to generate the matrix element here using the following command
psi4 --new-plugin fcidump

So if could you please help me in this regard then it would be very helpful.
Thanks in advance for the help.

Do you just need the normal FCIDUMP?

You don’t need the plugin in anymore.
With a current psi4 installation you can now generate fcidumps readily.
See examples here: http://psicode.org/psi4manual/master/api/psi4.driver.fcidump.html

1 Like

Hi hokru,
Thanks for your answer and I have seen the link.
But still I have confusion and I am unable to make it.
I have following input file and I would like to get matrix element for this case.

molecule N2 {
   N       0.0000   0.0000   0.0000
   N       0.0000   0.0000   2.1180
units au
}

sys.path.insert(0, './..')
import fcidump

set basis cc-pVDZ
set reference rhf
set scf_type PK
set e_convergence 1e-12
set d_convergence 1e-12
set ints_tolerance 0.0

set fcidump dumpfilename N2.ccpvdz.fcidump

energy('fcidump')

In the psi4conda in the following directory
psi4conda/share/psi4/samples/chemps2/

I tried with command psi4 input.dat (above input).

What psi4 version are you using? Below input works for current 1.3.2

The energy function needs to return its wavefunction object, which you input into the fcidump function.

Like this:

molecule N2 {
   N       0.0000   0.0000   0.0000
   N       0.0000   0.0000   2.1180
units au
}

set basis cc-pVDZ
set reference rhf
set scf_type PK
set e_convergence 1e-12
set d_convergence 1e-12
set ints_tolerance 0.0

e,wfn = energy('hf',return_wfn=True)
fcidump(wfn,fname='N2.ccpvdz.fcidump')
1 Like

Hi hokru,
Thanks for your quick answer.
After posting my question, I also did a try in the same way you mentioned and It works fine.
By the way, I have installed the binary version Psi4conda-1.3.2-py36-Linux-x86_64.sh.
Thanks!

Great! Please mark as solved if all is good :slight_smile:

1 Like

Oh yeah, it is solved.:slightly_smiling_face:
Thanks!

“Mark as solved” means that you click the “Solution” checkbox on the post that most directly answers your question. It should be right next to the heart, but if you see a triple dot, you may need to click that before it appears.

1 Like

Hi hokru,
I have another confusion, for the water molecule in the input file it is written as

set restricted_docc [ 1 , 0 , 0 , 0 ]
set active [ 5 , 0 , 4 , 2 ]
As water molecule is under c2v symmetry with the irreducible representations A1, A2, B1, B2.
But how these numbers are chosen for these irreducible representations?
Thanks for the time and answer!