mirror of https://github.com/pfloos/quack
216 lines
4.9 KiB
Fortran
216 lines
4.9 KiB
Fortran
subroutine ufBSE(nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI,eHF,eGW)
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! Unfold BSE@GW equations
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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
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integer,intent(in) :: nC
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integer,intent(in) :: nO
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integer,intent(in) :: nV
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integer,intent(in) :: nR
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integer,intent(in) :: nS
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double precision,intent(in) :: ENuc
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double precision,intent(in) :: ERHF
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double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
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double precision,intent(in) :: eHF(nBas)
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double precision,intent(in) :: eGW(nBas)
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! Local variables
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integer :: s
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integer :: i,j,k,l
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integer :: a,b,c,d
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integer :: ia,jb,kc,iajb,kcld
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integer,parameter :: maxH = 20
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double precision :: tmp
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integer :: n1h1p,n2h2p,nH
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double precision,external :: Kronecker_delta
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integer,allocatable :: order(:)
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double precision,allocatable :: H(:,:)
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double precision,allocatable :: X(:,:)
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double precision,allocatable :: Om(:)
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double precision,allocatable :: Z(:)
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! Output variables
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! Hello world
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write(*,*)
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write(*,*)'**********************************************'
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write(*,*)'| Unfolded BSE@GW calculation |'
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write(*,*)'**********************************************'
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write(*,*)
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! TDA for W
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write(*,*) 'Tamm-Dancoff approximation by default!'
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write(*,*)
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! Dimension of the supermatrix
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n1h1p = nO*nV
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n2h2p = nO*nO*nV*nV
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nH = n1h1p + n2h2p + n2h2p
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! Memory allocation
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allocate(order(nH),H(nH,nH),X(nH,nH),Om(nH),Z(nH))
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! Initialization
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H(:,:) = 0d0
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!---------------------------!
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! Compute BSE supermatrix !
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!---------------------------!
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! !
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! | A -Ve -Vh | !
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! | | !
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! H = | +Vh C2h2p 0 | !
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! | | !
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! | +Ve 0 C2p2h | !
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! !
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!---------------------------!
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!---------!
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! Block A !
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!---------!
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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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H(ia,jb) = (eGW(a) - eGW(i))*Kronecker_delta(i,j)*Kronecker_delta(a,b) &
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+ 2d0*ERI(i,b,a,j) - ERI(i,b,j,a)
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end do
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end do
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end do
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end do
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!----------------!
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! Blocks Vp & Ve !
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!----------------!
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iajb=0
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do i=nC+1,nO
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do a=nO+1,nBas-nR
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do j=nC+1,nO
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do b=nO+1,nBas-nR
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iajb = iajb + 1
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kc = 0
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do k=nC+1,nO
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do c=nO+1,nBas-nR
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kc = kc + 1
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tmp = sqrt(2d0)*Kronecker_delta(k,j)*ERI(b,a,c,i)
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H(n1h1p+iajb,kc ) = +tmp
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H(kc ,n1h1p+n2h2p+iajb) = -tmp
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tmp = sqrt(2d0)*Kronecker_delta(b,c)*ERI(a,k,i,j)
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H(n1h1p+n2h2p+iajb,kc ) = +tmp
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H(kc ,n1h1p+iajb) = -tmp
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end do
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end do
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end do
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end do
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end do
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end do
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!-------------!
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! Block 2h2p !
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!-------------!
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iajb = 0
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do i=nC+1,nO
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do a=nO+1,nBas-nR
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do j=nC+1,nO
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do b=nO+1,nBas-nR
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iajb = iajb + 1
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kcld = 0
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do k=nC+1,nO
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do c=nO+1,nBas-nR
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do l=nC+1,nO
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do d=nO+1,nBas-nR
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kcld = kcld + 1
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tmp = ((eHF(a) + eGW(b) - eHF(i) - eGW(j))*Kronecker_delta(i,k)*Kronecker_delta(a,c) &
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+ 2d0*ERI(a,k,i,c))*Kronecker_delta(j,l)*Kronecker_delta(b,d)
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H(n1h1p +iajb,n1h1p +kcld) = tmp
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H(n1h1p+n2h2p+iajb,n1h1p+n2h2p+kcld) = tmp
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end do
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end do
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end do
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end do
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end do
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end do
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end do
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end do
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!-------------------------!
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! Diagonalize supermatrix !
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!-------------------------!
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! call matout(nH,nH,H)
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call diagonalize_general_matrix(nH,H,Om,X)
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do s=1,nH
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order(s) = s
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end do
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call quick_sort(Om,order,nH)
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call set_order(X,order,nH,nH)
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!-----------------!
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! Compute weights !
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!-----------------!
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Z(:) = 0d0
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do s=1,nH
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do ia=1,n1h1p
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Z(s) = Z(s) + X(ia,s)**2
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end do
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end do
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!--------------!
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! Dump results !
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!--------------!
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write(*,*)'-------------------------------------------'
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write(*,*)' unfolded BSE excitation energies (eV) '
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write(*,*)'-------------------------------------------'
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write(*,'(1X,A1,1X,A3,1X,A1,1X,A15,1X,A1,1X,A15,1X,A1,1X,A15,1X)') &
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'|','#','|','Omega (eV)','|','Z','|'
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write(*,*)'-------------------------------------------'
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do s=1,min(nH,maxH)
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if(Z(s) > 1d-7) &
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write(*,'(1X,A1,1X,I3,1X,A1,1X,F15.6,1X,A1,1X,F15.6,1X,A1,1X)') &
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'|',s,'|',Om(s)*HaToeV,'|',Z(s),'|'
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end do
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write(*,*)'-------------------------------------------'
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write(*,*)
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end subroutine
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