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https://github.com/pfloos/quack
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186 lines
5.8 KiB
Fortran
186 lines
5.8 KiB
Fortran
subroutine RPA(singlet_manifold,triplet_manifold,nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI,e)
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! Perform a direct random phase approximation calculation
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implicit none
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include 'parameters.h'
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include 'quadrature.h'
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! Input variables
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logical,intent(in) :: singlet_manifold
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logical,intent(in) :: triplet_manifold
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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) :: e(nBas)
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double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
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! Local variables
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logical :: dRPA
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logical :: TDA
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logical :: BSE
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integer :: ispin
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double precision,allocatable :: Omega(:,:)
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double precision,allocatable :: XpY(:,:,:)
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double precision :: rho
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double precision :: EcRPA(nspin)
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logical :: AC
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integer :: iAC
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double precision :: lambda
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double precision,allocatable :: EcACRPA(:,:)
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double precision,allocatable :: EcAC(:,:)
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! Hello world
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write(*,*)
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write(*,*)'***********************************************'
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write(*,*)'| random-phase approximation calculation |'
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write(*,*)'***********************************************'
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write(*,*)
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! Initialization
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EcRPA(:) = 0d0
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! Switch off exchange for RPA
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dRPA = .true.
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! Switch off Tamm-Dancoff approximation for RPA
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TDA = .false.
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! Switch off Bethe-Salpeter equation for RPA
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BSE = .false.
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! Memory allocation
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allocate(Omega(nS,nspin),XpY(nS,nS,nspin))
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AC = .true.
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allocate(EcACRPA(nAC,nspin),EcAC(nAC,nspin))
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! Singlet manifold
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if(singlet_manifold) then
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ispin = 1
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call linear_response(ispin,dRPA,TDA,BSE,nBas,nC,nO,nV,nR,nS,1d0,e,ERI,rho, &
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EcRPA(ispin),Omega(:,ispin),XpY(:,:,ispin))
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call print_excitation('RPA ',ispin,nS,Omega(:,ispin))
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endif
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! Triplet manifold
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if(triplet_manifold) then
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ispin = 2
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call linear_response(ispin,dRPA,TDA,BSE,nBas,nC,nO,nV,nR,nS,1d0,e,ERI,rho, &
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EcRPA(ispin),Omega(:,ispin),XpY(:,:,ispin))
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call print_excitation('RPA ',ispin,nS,Omega(:,ispin))
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endif
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write(*,*)
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write(*,*)'-------------------------------------------------------------------------------'
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write(*,'(2X,A40,F15.6)') 'RPA@RPA correlation energy (singlet) =',EcRPA(1)
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write(*,'(2X,A40,F15.6)') 'RPA@RPA correlation energy (triplet) =',EcRPA(2)
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write(*,'(2X,A40,F15.6)') 'RPA@RPA correlation energy =',EcRPA(1) + EcRPA(2)
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write(*,'(2X,A40,F15.6)') 'RPA@RPA total energy =',ENuc + ERHF + EcRPA(1) + EcRPA(2)
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write(*,*)'-------------------------------------------------------------------------------'
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write(*,*)
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! Compute the correlation energy via the adiabatic connection
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if(AC) then
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write(*,*) '------------------------------------------------------'
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write(*,*) 'Adiabatic connection version of RPA correlation energy'
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write(*,*) '------------------------------------------------------'
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write(*,*)
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if(singlet_manifold) then
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ispin = 1
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EcACRPA(:,ispin) = 0d0
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write(*,*) '--------------'
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write(*,*) 'Singlet states'
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write(*,*) '--------------'
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write(*,*)
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write(*,*) '-----------------------------------------------------------------------------------'
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write(*,'(2X,A15,1X,A30,1X,A30)') 'lambda','EcRPA(lambda)','Tr(V x P_lambda)'
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write(*,*) '-----------------------------------------------------------------------------------'
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do iAC=1,nAC
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lambda = rAC(iAC)
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call linear_response(ispin,dRPA,TDA,BSE,nBas,nC,nO,nV,nR,nS,lambda,e,ERI,rho, &
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EcACRPA(iAC,ispin),Omega(:,ispin),XpY(:,:,ispin))
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call Ec_AC(ispin,dRPA,nBas,nC,nO,nV,nR,nS,ERI,XpY(:,:,ispin),EcAC(iAC,ispin))
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write(*,'(2X,F15.6,1X,F30.15,1X,F30.15)') lambda,EcACRPA(iAC,ispin),EcAC(iAC,ispin)
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end do
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write(*,*) '-----------------------------------------------------------------------------------'
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write(*,'(2X,A50,1X,F15.6)') ' Ec(RPA) via Gauss-Legendre quadrature:',0.5d0*dot_product(wAC,EcAC(:,ispin))
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write(*,*) '-----------------------------------------------------------------------------------'
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write(*,*)
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end if
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if(triplet_manifold) then
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ispin = 2
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EcACRPA(:,ispin) = 0d0
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write(*,*) '--------------'
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write(*,*) 'Triplet states'
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write(*,*) '--------------'
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write(*,*)
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write(*,*) '-----------------------------------------------------------------------------------'
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write(*,'(2X,A15,1X,A30,1X,A30)') 'lambda','EcRPA(lambda)','Tr(V x P_lambda)'
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write(*,*) '-----------------------------------------------------------------------------------'
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do iAC=1,nAC
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lambda = rAC(iAC)
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call linear_response(ispin,dRPA,TDA,BSE,nBas,nC,nO,nV,nR,nS,lambda,e,ERI,rho, &
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EcACRPA(iAC,ispin),Omega(:,ispin),XpY(:,:,ispin))
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call Ec_AC(ispin,dRPA,nBas,nC,nO,nV,nR,nS,ERI,XpY(:,:,ispin),EcAC(iAC,ispin))
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write(*,'(2X,F15.6,1X,F30.15,1X,F30.15)') lambda,EcACRPA(iAC,ispin),EcAC(iAC,ispin)
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end do
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write(*,*) '-----------------------------------------------------------------------------------'
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write(*,'(2X,A50,1X,F15.6)') ' Ec(RPA) via Gauss-Legendre quadrature:',0.5d0*dot_product(wAC,EcAC(:,ispin))
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write(*,*) '-----------------------------------------------------------------------------------'
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write(*,*)
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end if
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end if
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end subroutine RPA
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