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https://github.com/LCPQ/quantum_package
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32 lines
1.0 KiB
Fortran
32 lines
1.0 KiB
Fortran
program cisd
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implicit none
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integer :: i,k
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double precision, allocatable :: pt2(:), norm_pert(:), H_pert_diag(:),E_old(:)
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integer :: N_st, iter
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character*(64) :: perturbation
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N_st = N_states
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allocate (pt2(N_st), norm_pert(N_st), H_pert_diag(N_st),E_old(N_st))
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pt2 = 1.d0
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perturbation = "epstein_nesbet"
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E_old(1) = HF_energy
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do while (maxval(abs(pt2(1:N_st))) > 1.d-6)
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print*,'----'
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print*,''
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call H_apply_cisd_selection(perturbation,pt2, norm_pert, H_pert_diag, N_st)
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call diagonalize_CI
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print*,'N_det = ',N_det
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do i = 1, N_st
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print*,'state ',i
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print *, 'PT2 = ', pt2(i)
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print *, 'E = ', CI_energy(i)
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print *, 'E_before +PT2 = ', (E_old(i)+pt2(i))
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! print *, 'E+PT2_new= ', (E_old(1)+1.d0*pt2(1)+H_pert_diag(1))/(1.d0 +norm_pert(1))
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enddo
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E_old = CI_energy
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enddo
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deallocate(pt2,norm_pert,H_pert_diag)
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end
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