mirror of https://github.com/pfloos/quack
117 lines
2.2 KiB
Fortran
117 lines
2.2 KiB
Fortran
subroutine DIP_EOM_CCD_2h(nC,nO,nV,nR,eO,OOVV,OOOO,t)
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! DIP-EOM-CCD calculation up to 2h
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implicit none
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! Input variables
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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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double precision,intent(in) :: eO(nO)
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double precision,intent(in) :: OOVV(nO,nO,nV,nV)
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double precision,intent(in) :: OOOO(nO,nO,nO,nO)
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double precision,intent(in) :: t(nO,nO,nV,nV)
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! Local variables
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integer :: i,j,k,l,ij,kl
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integer :: a,b
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integer :: nOO
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double precision,external :: Kronecker_delta
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double precision,allocatable :: F(:,:)
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double precision,allocatable :: W(:,:,:,:)
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double precision,allocatable :: H(:,:)
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double precision,allocatable :: Om(:)
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! Hello world
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write(*,*)
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write(*,*)'********************'
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write(*,*)'| DIP-EOM-CCD (2h) |'
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write(*,*)'********************'
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write(*,*)
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! Size of the EOM Hamiltonian
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nOO = nO*(nO-1)/2
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! Memory allocation
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allocate(F(nO,nO),W(nO,nO,nO,nO),H(nOO,nOO),Om(nOO))
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! Form one-body terms
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do i=1,nO-nC
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do j=1,nO-nC
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F(i,j) = eO(i)*Kronecker_delta(i,j)
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do k=1,nO-nC
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do a=1,nV-nR
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do b=1,nV-nR
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F(i,j) = F(i,j) + 0.5d0*OOVV(i,k,a,b)*t(j,k,a,b)
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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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! Form two-body terms
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do i=1,nO-nC
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do j=1,nO-nC
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do k=1,nO-nC
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do l=1,nO-nC
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W(i,j,k,l) = OOOO(i,j,k,l)
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do a=1,nV-nR
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do b=a+1,nV-nR
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W(i,j,k,l) = W(i,j,k,l) + OOVV(i,j,a,b)*t(i,j,a,b)
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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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! Form EOM Hamiltonian
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ij = 0
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do i=1,nO-nC
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do j=i+1,nO-nC
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ij = ij + 1
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kl = 0
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do k=1,nO-nC
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do l=k+1,nO-nC
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kl = kl + 1
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H(ij,kl) = - F(i,k)*Kronecker_delta(j,l) - Kronecker_delta(i,k)*F(j,l) + W(i,j,k,l)
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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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! Diagonalize EOM Hamiltonian
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if(nOO > 0) call diagonalize_matrix(nOO,H,Om)
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! Dump results
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call print_excitation_energies('DIP-EOM-CCD','spinorbital',nOO,Om)
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end subroutine
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