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qp_plugins_scemama/devel/general_mrci/mrci.irp.f

78 lines
2.0 KiB
Fortran

program cisd
implicit none
BEGIN_DOC
! Multi-Reference Configuration Interaction with Single and Double excitations.
!
! This program takes a reference wave function as input and
! and performs all single and double excitations on top of it, disregarding
! spatial symmetry and compute the "n_states" lowest eigenstates of that CI
! matrix (see :option:`determinants n_states`).
!
END_DOC
PROVIDE N_states
read_wf = .True.
SOFT_TOUCH read_wf
call run
end
subroutine run
implicit none
integer :: i,k
double precision :: cisdq(N_states), delta_e
double precision,external :: diag_h_mat_elem
if(do_singles)then
if(do_doubles)then
call H_apply_cisd
else
call H_apply_cis
endif
else
if(do_doubles)then
call H_apply_cid
else
stop "do_singles and do_doubles are both False"
endif
endif
psi_coef = ci_eigenvectors
SOFT_TOUCH psi_coef
call save_wavefunction
call ezfio_set_general_mrci_energy(CI_energy)
do i = 1,N_states
k = maxloc(dabs(psi_coef_sorted(1:N_det,i)),dim=1)
delta_E = CI_electronic_energy(i) - diag_h_mat_elem(psi_det_sorted(1,1,k),N_int)
cisdq(i) = CI_energy(i) + delta_E * (1.d0 - psi_coef_sorted(k,i)**2)
enddo
print *, 'N_det = ', N_det
print*,''
print*,'******************************'
print *, 'MR-CI Energies'
do i = 1,N_states
print *, i, CI_energy(i)
enddo
print*,''
print*,'******************************'
print *, 'MR-CI+Q Energies'
do i = 1,N_states
print *, i, cisdq(i)
enddo
if (N_states > 1) then
print*,''
print*,'******************************'
print*,'Excitation energies (au) (CISD+Q)'
do i = 2, N_states
print*, i ,CI_energy(i) - CI_energy(1), cisdq(i) - cisdq(1)
enddo
print*,''
print*,'******************************'
print*,'Excitation energies (eV) (CISD+Q)'
do i = 2, N_states
print*, i ,(CI_energy(i) - CI_energy(1))/0.0367502d0, &
(cisdq(i) - cisdq(1)) / 0.0367502d0
enddo
endif
end