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mirror of https://github.com/pfloos/quack synced 2024-11-09 07:33:55 +01:00
quack/src/MBPT/Bethe_Salpeter_ZAB_matrix_dynamic.f90

103 lines
3.1 KiB
Fortran

subroutine Bethe_Salpeter_ZAB_matrix_dynamic(eta,nBas,nC,nO,nV,nR,nS,lambda,eGW,OmRPA,rho_RPA,OmBSE, &
ZAp,ZAm,ZBp,ZBm)
! Compute the dynamic part of the renormalization for 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) :: rho_RPA(nBas,nBas,nS)
double precision,intent(in) :: OmBSE
! Local variables
integer :: maxS
double precision :: chi_Ap,chi_Bp,eps_Ap,eps_Bp
double precision :: chi_Am,chi_Bm,eps_Am,eps_Bm
integer :: i,j,a,b,ia,jb,kc
! Output variables
double precision,intent(out) :: ZAp(nS,nS)
double precision,intent(out) :: ZAm(nS,nS)
double precision,intent(out) :: ZBp(nS,nS)
double precision,intent(out) :: ZBm(nS,nS)
! Initialization
ZAp(:,:) = 0d0
ZAm(:,:) = 0d0
ZBp(:,:) = 0d0
ZBm(:,:) = 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_Ap = 0d0
chi_Am = 0d0
chi_Bp = 0d0
chi_Bm = 0d0
do kc=1,maxS
eps_Ap = + OmBSE - OmRPA(kc) - (eGW(a) - eGW(j))
chi_Ap = chi_Ap + rho_RPA(i,j,kc)*rho_RPA(a,b,kc)*(eps_Ap**2 - eta**2)/(eps_Ap**2 + eta**2)**2
eps_Ap = + OmBSE - OmRPA(kc) - (eGW(b) - eGW(i))
chi_Ap = chi_Ap + rho_RPA(i,j,kc)*rho_RPA(a,b,kc)*(eps_Ap**2 - eta**2)/(eps_Ap**2 + eta**2)**2
eps_Am = - OmBSE - OmRPA(kc) - (eGW(a) - eGW(j))
chi_Am = chi_Am + rho_RPA(i,j,kc)*rho_RPA(a,b,kc)*(eps_Am**2 - eta**2)/(eps_Am**2 + eta**2)**2
eps_Am = - OmBSE - OmRPA(kc) - (eGW(b) - eGW(i))
chi_Am = chi_Am + rho_RPA(i,j,kc)*rho_RPA(a,b,kc)*(eps_Am**2 - eta**2)/(eps_Am**2 + eta**2)**2
eps_Bp = + OmBSE - OmRPA(kc) - (eGW(a) - eGW(b))
chi_Bp = chi_Bp + rho_RPA(i,b,kc)*rho_RPA(a,j,kc)*(eps_Bp**2 - eta**2)/(eps_Bp**2 + eta**2)**2
eps_Bp = + OmBSE - OmRPA(kc) - (eGW(j) - eGW(i))
chi_Bp = chi_Bp + rho_RPA(i,b,kc)*rho_RPA(a,j,kc)*(eps_Bp**2 - eta**2)/(eps_Bp**2 + eta**2)**2
eps_Bm = - OmBSE - OmRPA(kc) - (eGW(a) - eGW(b))
chi_Bm = chi_Bm + rho_RPA(i,b,kc)*rho_RPA(a,j,kc)*(eps_Bm**2 - eta**2)/(eps_Bm**2 + eta**2)**2
eps_Bm = - OmBSE - OmRPA(kc) - (eGW(j) - eGW(i))
chi_Bm = chi_Bm + rho_RPA(i,b,kc)*rho_RPA(a,j,kc)*(eps_Bm**2 - eta**2)/(eps_Bm**2 + eta**2)**2
enddo
ZAp(ia,jb) = ZAp(ia,jb) + 2d0*lambda*chi_Ap
ZAm(ia,jb) = ZAm(ia,jb) - 2d0*lambda*chi_Am
ZBp(ia,jb) = ZBp(ia,jb) + 2d0*lambda*chi_Bp
ZBm(ia,jb) = ZBm(ia,jb) - 2d0*lambda*chi_Bm
enddo
enddo
enddo
enddo
end subroutine Bethe_Salpeter_ZAB_matrix_dynamic