I would like to print the CI coefficients after performing a DMRG-SCF simulation.

The output file contains the coefficients of the important determinants by default in CASSCF simulations. It is also possible to print all coefficients by changing the number of important determinants using *num_dets_print*. However, this does not seem to work in DMRG-SCF simulations.

Also, I found a function called *getFCIcoefficient* in the library of DMRG.h. However, I am getting a NameError message when I tried to use this function as follows

molecule {

0 1

O

H 1 0.9618

H 1 0.9618 2 102.425

}set {

basis cc-pVTZ

reference rhf

scf_type direct

e_convergence 1e-12

d_convergence 1e-10

ints_tolerance 0.0`dmrg_irrep 0 dmrg_multiplicity 1 restricted_docc [1, 0, 0, 0] active [4, 0, 1, 3] dmrg_sweep_states [ 200, 500, 1000, 1000 ] dmrg_sweep_energy_conv [ 1e-8, 1e-8, 1e-8, 1e-8 ] dmrg_sweep_dvdson_rtol [ 1e-4, 1e-4, 1e-4, 1e-4 ] dmrg_sweep_max_sweeps [ 5, 5, 5, 100 ] dmrg_sweep_noise_prefac [ 0.03, 0.03, 0.03, 0.0 ]`

}

scf_e, scf_wfn = energy(‘dmrg-scf’, return_wfn=True)

cicoeff1 = getFCIcoefficient([1,1,0,0,1,1,1,0],[1,1,0,0,1,1,1,0],False)

print(cicoeff1)

Finally, I tried to follow the method suggested in a previous post. Although the printed number of determinants is correct, all the coefficients appear to be zero.

Is there a method that prints the converged CI vector with the corresponding determinant indices after a DMRG-SCF simulation?

Thank you in advance.

Best,

Onur