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https://github.com/pfloos/quack
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146 lines
5.3 KiB
Fortran
146 lines
5.3 KiB
Fortran
subroutine Bethe_Salpeter(TDA_W,TDA,dTDA,singlet_manifold,triplet_manifold,eta, &
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nBas,nC,nO,nV,nR,nS,ERI,eW,eGW,OmRPA,XpY_RPA,XmY_RPA,rho_RPA,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_W
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logical,intent(in) :: TDA
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logical,intent(in) :: dTDA
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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_RPA(nS,nS,nspin)
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double precision :: XmY_RPA(nS,nS,nspin)
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double precision :: rho_RPA(nBas,nBas,nS,nspin)
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! Local variables
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logical :: evDyn = .true.
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logical :: W_BSE = .false.
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integer :: ispin
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integer :: isp_W
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double precision,allocatable :: OmBSE(:,:)
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double precision,allocatable :: XpY_BSE(:,:,:)
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double precision,allocatable :: XmY_BSE(:,:,:)
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double precision,allocatable :: rho_BSE(:,:,:,:)
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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),XpY_BSE(nS,nS,nspin),XmY_BSE(nS,nS,nspin))
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if(W_BSE) allocate(rho_BSE(nBas,nBas,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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isp_W = 1
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EcBSE(ispin) = 0d0
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! Compute (singlet) RPA screening
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call linear_response(isp_W,.true.,TDA_W,.false.,eta,nBas,nC,nO,nV,nR,nS,1d0,eW,ERI, &
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rho_RPA(:,:,:,ispin),EcRPA(ispin),OmRPA(:,ispin),XpY_RPA(:,:,ispin),XmY_RPA(:,:,ispin))
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call excitation_density(nBas,nC,nO,nR,nS,ERI,XpY_RPA(:,:,ispin),rho_RPA(:,:,:,ispin))
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! Compute BSE excitation energies
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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_RPA(:,:,:,ispin),EcBSE(ispin),OmBSE(:,ispin),XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin))
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call print_excitation('BSE ',ispin,nS,OmBSE(:,ispin))
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! Compute the dynamical screening at the BSE level
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if(W_BSE) call excitation_density(nBas,nC,nO,nR,nS,ERI,XpY_BSE(:,:,ispin),rho_BSE(:,:,:,ispin))
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! Compute dynamic correction for BSE via perturbation theory
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if(evDyn) then
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call Bethe_Salpeter_dynamic_perturbation_iterative(TDA,dTDA,eta,nBas,nC,nO,nV,nR,nS,eGW(:),OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin),rho_RPA(:,:,:,ispin))
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else
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if(W_BSE) then
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call Bethe_Salpeter_dynamic_perturbation(TDA,dTDA,eta,nBas,nC,nO,nV,nR,nS,eGW(:),OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin),rho_BSE(:,:,:,ispin))
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else
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call Bethe_Salpeter_dynamic_perturbation(TDA,dTDA,eta,nBas,nC,nO,nV,nR,nS,eGW(:),OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin),rho_RPA(:,:,:,ispin))
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end if
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end if
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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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isp_W = 1
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EcBSE(ispin) = 0d0
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! Compute (singlet) RPA screening
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call linear_response(isp_W,.true.,TDA_W,.false.,eta,nBas,nC,nO,nV,nR,nS,1d0,eW,ERI, &
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rho_RPA(:,:,:,ispin),EcRPA(ispin),OmRPA(:,ispin),XpY_RPA(:,:,ispin),XmY_RPA(:,:,ispin))
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call excitation_density(nBas,nC,nO,nR,nS,ERI,XpY_RPA(:,:,ispin),rho_RPA(:,:,:,ispin))
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! Compute BSE excitation energies
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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_RPA(:,:,:,ispin),EcBSE(ispin),OmBSE(:,ispin),XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin))
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call print_excitation('BSE ',ispin,nS,OmBSE(:,ispin))
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! Compute the dynamical screening at the BSE level
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if(W_BSE) call excitation_density(nBas,nC,nO,nR,nS,ERI,XpY_BSE(:,:,ispin),rho_BSE(:,:,:,ispin))
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! Compute dynamic correction for BSE via perturbation theory
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if(evDyn) then
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call Bethe_Salpeter_dynamic_perturbation_iterative(TDA,dTDA,eta,nBas,nC,nO,nV,nR,nS,eGW(:),OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin),rho_RPA(:,:,:,ispin))
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else
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if(W_BSE) then
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call Bethe_Salpeter_dynamic_perturbation(TDA,dTDA,eta,nBas,nC,nO,nV,nR,nS,eGW(:),OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin),rho_BSE(:,:,:,ispin))
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else
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call Bethe_Salpeter_dynamic_perturbation(TDA,dTDA,eta,nBas,nC,nO,nV,nR,nS,eGW(:),OmRPA(:,ispin),OmBSE(:,ispin), &
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XpY_BSE(:,:,ispin),XmY_BSE(:,:,ispin),rho_RPA(:,:,:,ispin))
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end if
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end if
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end if
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end subroutine Bethe_Salpeter
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