kohn_sham_rs

The Range-separated Kohn-Sham module performs Restricted Kohn-Sham calculations (the spatial part of the MOs is common for alpha and beta spinorbitals) where the coulomb interaction is partially treated using exact exchange. The splitting of the interaction between long- and short-range is determined by the range-separation parameter ao_two_e_erf_ints mu_erf. The long-range part of the interaction is explicitly treated with exact exchange, and the short-range part of the interaction is treated with appropriate DFT functionals.

The Range-separated Kohn-Sham in an SCF and therefore is based on the scf_utils structure. It performs the following actions:

  1. Compute/Read all the one- and two-electron integrals, and store them in memory
  2. Check in the EZFIO database if there is a set of MOs. If there is, it will read them as initial guess. Otherwise, it will create a guess.
  3. Perform the SCF iterations

The definition of the Fock matrix is in kohn_sham_rs fock_matrix_rs_ks.irp.f For the keywords related to the SCF procedure, see the scf_utils directory where you will find all options. The main are: # scf_utils thresh_scf # scf_utils level_shift

At each iteration, the MOs are saved in the EZFIO database. Hence, if the calculation crashes for any unexpected reason, the calculation can be restarted by running again the SCF with the same EZFIO database.

The DIIS algorithm is implemented, as well as the level-shifting method. If the SCF does not converge, try again with a higher value of level_shift.

To start a calculation from scratch, the simplest way is to remove the mo_basis directory from the EZFIO database, and run the SCF again.

EZFIO parameters

energy

Energy range separated hybrid

Programs

Providers

ao_potential_alpha_xc

File : pot_functionals.irp.f

double precision, allocatable   :: ao_potential_alpha_xc        (ao_num,ao_num)
double precision, allocatable   :: ao_potential_beta_xc (ao_num,ao_num)

Needs:

  • ao_num

Needed by:

ao_potential_beta_xc

File : pot_functionals.irp.f

double precision, allocatable   :: ao_potential_alpha_xc        (ao_num,ao_num)
double precision, allocatable   :: ao_potential_beta_xc (ao_num,ao_num)

Needs:

  • ao_num

Needed by:

e_correlation_dft

File : pot_functionals.irp.f

double precision        :: e_correlation_dft

Needs:

Needed by:

e_exchange_dft

File : pot_functionals.irp.f

double precision        :: e_exchange_dft

Needs:

Needed by:

fock_matrix_alpha_no_xc_ao

File : fock_matrix_rs_ks.irp.f

double precision, allocatable   :: fock_matrix_alpha_no_xc_ao   (ao_num,ao_num)
double precision, allocatable   :: fock_matrix_beta_no_xc_ao    (ao_num,ao_num)

Mono electronic an Coulomb matrix in AO basis set

Needs:

  • ao_num

Needed by:

fock_matrix_beta_no_xc_ao

File : fock_matrix_rs_ks.irp.f

double precision, allocatable   :: fock_matrix_alpha_no_xc_ao   (ao_num,ao_num)
double precision, allocatable   :: fock_matrix_beta_no_xc_ao    (ao_num,ao_num)

Mono electronic an Coulomb matrix in AO basis set

Needs:

  • ao_num

Needed by:

fock_matrix_energy

File : rs_ks_energy.irp.f

double precision        :: rs_ks_energy
double precision        :: two_e_energy
double precision        :: one_e_energy
double precision        :: fock_matrix_energy
double precision        :: trace_potential_xc

Range-separated Kohn-Sham energy containing the nuclear repulsion energy, and the various components of this quantity.

Needs:

Needed by:

one_e_energy

File : rs_ks_energy.irp.f

double precision        :: rs_ks_energy
double precision        :: two_e_energy
double precision        :: one_e_energy
double precision        :: fock_matrix_energy
double precision        :: trace_potential_xc

Range-separated Kohn-Sham energy containing the nuclear repulsion energy, and the various components of this quantity.

Needs:

Needed by:

rs_ks_energy

File : rs_ks_energy.irp.f

double precision        :: rs_ks_energy
double precision        :: two_e_energy
double precision        :: one_e_energy
double precision        :: fock_matrix_energy
double precision        :: trace_potential_xc

Range-separated Kohn-Sham energy containing the nuclear repulsion energy, and the various components of this quantity.

Needs:

Needed by:

trace_potential_xc

File : rs_ks_energy.irp.f

double precision        :: rs_ks_energy
double precision        :: two_e_energy
double precision        :: one_e_energy
double precision        :: fock_matrix_energy
double precision        :: trace_potential_xc

Range-separated Kohn-Sham energy containing the nuclear repulsion energy, and the various components of this quantity.

Needs:

Needed by:

two_e_energy

File : rs_ks_energy.irp.f

double precision        :: rs_ks_energy
double precision        :: two_e_energy
double precision        :: one_e_energy
double precision        :: fock_matrix_energy
double precision        :: trace_potential_xc

Range-separated Kohn-Sham energy containing the nuclear repulsion energy, and the various components of this quantity.

Needs:

Needed by:

Subroutines / functions

check_coherence_functional:()

File : rs_ks_scf.irp.f

subroutine check_coherence_functional

Needs:

  • exchange_functional
  • correlation_functional

Called by:

  • rs_ks_scf()