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mirror of https://github.com/pfloos/quack synced 2024-06-20 04:02:18 +02:00
quack/src/GW/ufXBSE.f90

269 lines
6.0 KiB
Fortran

subroutine ufXBSE(nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI,eHF,OmRPA,sERI)
! Unfolded BSE+ equations
implicit none
include 'parameters.h'
! Input variables
integer,intent(in) :: nBas
integer,intent(in) :: nC
integer,intent(in) :: nO
integer,intent(in) :: nV
integer,intent(in) :: nR
integer,intent(in) :: nS
double precision,intent(in) :: ENuc
double precision,intent(in) :: ERHF
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
double precision,intent(in) :: eHF(nBas)
double precision,intent(in) :: OmRPA(nS)
double precision,intent(in) :: sERI(nBas,nBas,nS)
! Local variables
integer :: s
integer :: i,j,k,l
integer :: a,b,c,d
integer :: ia,jb,kc,iajb,kcld
integer,parameter :: maxH = 20
double precision :: eps1,eps2
double precision :: Ve,Vh,C2h2p
integer :: n1h1p,n2h2p,nH
double precision,external :: Kronecker_delta
double precision,allocatable :: H(:,:)
double precision,allocatable :: X(:,:)
double precision,allocatable :: Om(:)
double precision,allocatable :: Z(:)
! Output variables
! Hello world
write(*,*)
write(*,*)'**********************************************'
write(*,*)'| Unfolded BSE+ calculation |'
write(*,*)'**********************************************'
write(*,*)
! TDA for W
write(*,*) 'Tamm-Dancoff approximation by default!'
write(*,*)
! Dimension of the supermatrix
n1h1p = nO*nV
n2h2p = nO*nO*nV*nV
nH = n1h1p + n2h2p
! Memory allocation
allocate(H(nH,nH),X(nH,nH),Om(nH),Z(nH))
! Initialization
H(:,:) = 0d0
!---------------------------!
! Compute BSE+ supermatrix !
!---------------------------!
! !
! | A Ve-Vh | !
! H = | | !
! | Ve-Vh C2h2p | !
! !
!---------------------------!
!---------!
! Block A !
!---------!
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
H(ia,jb) = (eHF(a) - eHF(i))*Kronecker_delta(i,j)*Kronecker_delta(a,b) &
+ 2d0*ERI(i,b,a,j) - ERI(i,b,j,a)
do kc=1,nS
do l=nC+1,nO
eps1 = 1d0/(eHF(a) - eHF(l) + OmRPA(kc))
eps2 = 1d0/(eHF(b) - eHF(l) + OmRPA(kc))
H(ia,jb) = H(ia,jb) + Kronecker_delta(i,j)*sERI(a,l,kc)*sERI(b,l,kc)*(eps1+eps2)
enddo
do d=nO+1,nBas-nR
eps1 = 1d0/(- eHF(i) + eHF(d) + OmRPA(kc))
eps2 = 1d0/(- eHF(j) + eHF(d) + OmRPA(kc))
H(ia,jb) = H(ia,jb) + Kronecker_delta(a,b)*sERI(i,d,kc)*sERI(j,d,kc)*(eps1+eps2)
enddo
eps1 = 1d0/(eHF(a) - eHF(i) + OmRPA(kc))
eps2 = 1d0/(eHF(b) - eHF(j) + OmRPA(kc))
H(ia,jb) = H(ia,jb) - 2d0*sERI(i,a,kc)*sERI(j,b,kc)*(eps1+eps2)
end do
end do
end do
end do
end do
!----------------!
! Blocks Vp & Ve !
!----------------!
iajb=0
do i=nC+1,nO
do a=nO+1,nBas-nR
do j=nC+1,nO
do b=nO+1,nBas-nR
iajb = iajb + 1
kc = 0
do k=nC+1,nO
do c=nO+1,nBas-nR
kc = kc + 1
Ve = sqrt(2d0)*Kronecker_delta(k,j)*ERI(b,a,c,i)
Vh = sqrt(2d0)*Kronecker_delta(b,c)*ERI(a,k,i,j)
H(n1h1p+iajb,kc ) = Ve - Vh
H(kc ,n1h1p+iajb) = Ve - Vh
end do
end do
end do
end do
end do
end do
! iajb=0
! ia = 0
! do i=nC+1,nO
! do a=nO+1,nBas-nR
! ia = ia + 1
! do j=nC+1,nO
! do b=nO+1,nBas-nR
! iajb = iajb + 1
! kc = 0
! do k=nC+1,nO
! do c=nO+1,nBas-nR
! kc = kc + 1
! Ve = sqrt(2d0)*Kronecker_delta(k,j)*sERI(b,c,ia)
! Vh = sqrt(2d0)*Kronecker_delta(b,c)*sERI(k,j,ia)
! H(n1h1p+iajb,kc ) = Ve - Vh
! H(kc ,n1h1p+iajb) = Ve - Vh
!
! end do
! end do
! end do
! end do
! end do
! end do
!-------------!
! Block 2h2p !
!-------------!
iajb = 0
do i=nC+1,nO
do a=nO+1,nBas-nR
do j=nC+1,nO
do b=nO+1,nBas-nR
iajb = iajb + 1
kcld = 0
do k=nC+1,nO
do c=nO+1,nBas-nR
do l=nC+1,nO
do d=nO+1,nBas-nR
kcld = kcld + 1
C2h2p = ((eHF(a) + eHF(b) - eHF(i) - eHF(j))*Kronecker_delta(i,k)*Kronecker_delta(a,c) &
+ 2d0*ERI(a,k,i,c))*Kronecker_delta(j,l)*Kronecker_delta(b,d)
H(n1h1p+iajb,n1h1p+kcld) = C2h2p
end do
end do
end do
end do
end do
end do
end do
end do
! iajb = 0
! ia = 0
! do i=nC+1,nO
! do a=nO+1,nBas-nR
! ia = ia + 1
! do j=nC+1,nO
! do b=nO+1,nBas-nR
! iajb = iajb + 1
! H(n1h1p+iajb,n1h1p+iajb) = Om(ia) + eHF(b) - eHF(j)
! end do
! end do
! end do
! end do
!-------------------------!
! Diagonalize supermatrix !
!-------------------------!
X(:,:) = H(:,:)
call diagonalize_matrix(nH,X,Om)
!-----------------!
! Compute weights !
!-----------------!
Z(:) = 0d0
do s=1,nH
do ia=1,n1h1p
Z(s) = Z(s) + X(ia,s)**2
end do
end do
!--------------!
! Dump results !
!--------------!
write(*,*)'-------------------------------------------'
write(*,*)' BSE+ excitation energies (eV) '
write(*,*)'-------------------------------------------'
write(*,'(1X,A1,1X,A3,1X,A1,1X,A15,1X,A1,1X,A15,1X,A1,1X,A15,1X)') &
'|','#','|','Omega (eV)','|','Z','|'
write(*,*)'-------------------------------------------'
do s=1,min(nH,maxH)
if(Z(s) > 1d-7) &
write(*,'(1X,A1,1X,I3,1X,A1,1X,F15.6,1X,A1,1X,F15.6,1X,A1,1X)') &
'|',s,'|',Om(s)*HaToeV,'|',Z(s),'|'
enddo
write(*,*)'-------------------------------------------'
write(*,*)
end subroutine