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https://github.com/pfloos/quack
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76 lines
1.7 KiB
Fortran
76 lines
1.7 KiB
Fortran
subroutine Bethe_Salpeter_A_matrix_dynamic(eta,nBas,nC,nO,nV,nR,nS,lambda,eGW,OmRPA,OmBSE,rho,A_dyn)
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! Compute the dynamic part of the Bethe-Salpeter equation matrices
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implicit none
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include 'parameters.h'
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! Input variables
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integer,intent(in) :: nBas,nC,nO,nV,nR,nS
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double precision,intent(in) :: eta
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double precision,intent(in) :: lambda
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double precision,intent(in) :: eGW(nBas)
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double precision,intent(in) :: OmRPA(nS)
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double precision,intent(in) :: OmBSE
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double precision,intent(in) :: rho(nBas,nBas,nS)
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! Local variables
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integer :: maxS
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double precision :: chi
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double precision :: eps
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integer :: i,j,a,b,ia,jb,kc
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! Output variables
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double precision,intent(out) :: A_dyn(nS,nS)
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! Initialization
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A_dyn(:,:) = 0d0
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! Number of poles taken into account
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maxS = nS
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! Build dynamic A matrix
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ia = 0
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do i=nC+1,nO
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do a=nO+1,nBas-nR
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ia = ia + 1
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jb = 0
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do j=nC+1,nO
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do b=nO+1,nBas-nR
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jb = jb + 1
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chi = 0d0
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do kc=1,maxS
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chi = chi + rho(i,j,kc)*rho(a,b,kc)*OmRPA(kc)/(OmRPA(kc)**2 + eta**2)
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enddo
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A_dyn(ia,jb) = A_dyn(ia,jb) - 4d0*lambda*chi
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chi = 0d0
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do kc=1,maxS
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eps = + OmBSE - OmRPA(kc) - (eGW(a) - eGW(j))
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chi = chi + rho(i,j,kc)*rho(a,b,kc)*eps/(eps**2 + eta**2)
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eps = + OmBSE - OmRPA(kc) - (eGW(b) - eGW(i))
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chi = chi + rho(i,j,kc)*rho(a,b,kc)*eps/(eps**2 + eta**2)
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enddo
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A_dyn(ia,jb) = A_dyn(ia,jb) - 2d0*lambda*chi
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enddo
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enddo
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enddo
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enddo
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end subroutine Bethe_Salpeter_A_matrix_dynamic
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