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https://github.com/pfloos/quack
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92 lines
3.0 KiB
Fortran
92 lines
3.0 KiB
Fortran
subroutine Bethe_Salpeter(TDA,singlet_manifold,triplet_manifold,eta, &
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nBas,nC,nO,nV,nR,nS,ERI,eW,eGW,OmRPA,XpY,XmY,rho,EcRPA,EcBSE)
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! Compute the Bethe-Salpeter excitation energies
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implicit none
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include 'parameters.h'
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! Input variables
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logical,intent(in) :: TDA
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logical,intent(in) :: singlet_manifold
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logical,intent(in) :: triplet_manifold
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double precision,intent(in) :: eta
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integer,intent(in) :: nBas,nC,nO,nV,nR,nS
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double precision,intent(in) :: eW(nBas)
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double precision,intent(in) :: eGW(nBas)
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double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
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double precision :: OmRPA(nS,nspin)
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double precision :: XpY(nS,nS,nspin)
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double precision :: XmY(nS,nS,nspin)
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double precision :: rho(nBas,nBas,nS,nspin)
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! Local variables
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integer :: ispin
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double precision,allocatable :: OmBSE(:,:)
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! Output variables
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double precision,intent(out) :: EcRPA(nspin)
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double precision,intent(out) :: EcBSE(nspin)
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! Memory allocation
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allocate(OmBSE(nS,nspin))
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!-------------------
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! Singlet manifold
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!-------------------
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if(singlet_manifold) then
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ispin = 1
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EcBSE(ispin) = 0d0
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call linear_response(ispin,.true.,TDA,.false.,eta,nBas,nC,nO,nV,nR,nS,1d0,eW,ERI, &
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rho(:,:,:,ispin),EcRPA(ispin),OmRPA(:,ispin),XpY(:,:,ispin),XmY(:,:,ispin))
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call excitation_density(nBas,nC,nO,nR,nS,ERI,XpY(:,:,ispin),rho(:,:,:,ispin))
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OmBSE(:,ispin) = OmRPA(:,ispin)
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call linear_response(ispin,.true.,TDA,.true.,eta,nBas,nC,nO,nV,nR,nS,1d0,eGW,ERI, &
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rho(:,:,:,ispin),EcBSE(ispin),OmBSE(:,ispin),XpY(:,:,ispin),XmY(:,:,ispin))
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call print_excitation('BSE ',ispin,nS,OmBSE(:,ispin))
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! Compute dynamic correction for BSE via perturbation theory
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call Bethe_Salpeter_dynamic_perturbation(TDA,eta,nBas,nC,nO,nV,nR,nS,OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY(:,:,ispin),XmY(:,:,ispin),rho(:,:,:,ispin))
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end if
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!-------------------
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! Triplet manifold
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!-------------------
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if(triplet_manifold) then
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ispin = 2
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EcBSE(ispin) = 0d0
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call linear_response(ispin,.true.,TDA,.false.,eta,nBas,nC,nO,nV,nR,nS,1d0,eW,ERI, &
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rho(:,:,:,ispin),EcRPA(ispin),OmRPA(:,ispin),XpY(:,:,ispin),XmY(:,:,ispin))
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call excitation_density(nBas,nC,nO,nR,nS,ERI,XpY(:,:,ispin),rho(:,:,:,ispin))
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OmBSE(:,ispin) = OmRPA(:,ispin)
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call linear_response(ispin,.true.,TDA,.true.,eta,nBas,nC,nO,nV,nR,nS,1d0,eGW,ERI, &
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rho(:,:,:,ispin),EcBSE(ispin),OmBSE(:,ispin),XpY(:,:,ispin),XmY(:,:,ispin))
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call print_excitation('BSE ',ispin,nS,OmBSE(:,ispin))
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! Compute dynamic correction for BSE via perturbation theory
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call Bethe_Salpeter_dynamic_perturbation(TDA,eta,nBas,nC,nO,nV,nR,nS,OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY(:,:,ispin),XmY(:,:,ispin),rho(:,:,:,ispin))
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end if
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end subroutine Bethe_Salpeter
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