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mirror of https://github.com/pfloos/quack synced 2024-12-23 04:43:42 +01:00

dynamic screening in BSE

This commit is contained in:
Pierre-Francois Loos 2020-04-23 23:13:44 +02:00
parent 01e9f785c2
commit f38c07a444

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