mirror of https://github.com/pfloos/quack
117 lines
2.2 KiB
Fortran
117 lines
2.2 KiB
Fortran
subroutine DEA_EOM_CCD_2p(nC,nO,nV,nR,eV,OOVV,VVVV,t)
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! DEA-EOM-CCD calculation up to 2p
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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) :: eV(nV)
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double precision,intent(in) :: OOVV(nO,nO,nV,nV)
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double precision,intent(in) :: VVVV(nV,nV,nV,nV)
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double precision,intent(in) :: t(nO,nO,nV,nV)
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! Local variables
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integer :: a,b,c,d,ab,cd
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integer :: i,j
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integer :: nVV
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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(*,*)'| DEA-EOM-CCD (2p) |'
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write(*,*)'********************'
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write(*,*)
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! Size of the EOM Hamiltonian
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nVV = nV*(nV-1)/2
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! Memory allocation
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allocate(F(nV,nV),W(nV,nV,nV,nV),H(nVV,nVV),Om(nVV))
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! Form one-body terms
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do a=1,nV-nR
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do b=1,nV-nR
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F(a,b) = eV(a)*Kronecker_delta(a,b)
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do i=1,nO-nR
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do j=1,nO-nR
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do c=1,nV-nC
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F(a,b) = F(a,b) - 0.5d0*OOVV(i,j,b,c)*t(i,j,a,c)
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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 a=1,nV-nR
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do b=1,nV-nR
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do c=1,nV-nR
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do d=1,nV-nR
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W(a,b,c,d) = VVVV(a,b,c,d)
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do i=1,nO-nC
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do j=i+1,nO-nC
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W(a,b,c,d) = W(a,b,c,d) + 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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ab = 0
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do a=1,nV-nR
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do b=a+1,nV-nR
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ab = ab + 1
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cd = 0
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do c=1,nV-nR
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do d=c+1,nV-nR
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cd = cd + 1
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H(ab,cd) = F(a,c)*Kronecker_delta(b,d) + Kronecker_delta(a,c)*F(b,d) + W(a,b,c,d)
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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(nVV > 0) call diagonalize_matrix(nVV,H,Om)
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! Dump results
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call print_excitation_energies('DEA-EOM-CCD','spinorbital',nVV,Om)
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end subroutine
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