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mirror of https://github.com/pfloos/quack synced 2024-12-22 20:34:46 +01:00
QuAcK/src/GW/UGW_phBSE.f90

201 lines
7.0 KiB
Fortran

subroutine UGW_phBSE(exchange_kernel,TDA_W,TDA,dBSE,dTDA,spin_conserved,spin_flip,eta,nBas,nC,nO,nV,nR,nS, &
S,ERI_aaaa,ERI_aabb,ERI_bbbb,dipole_int_aa,dipole_int_bb,cW,eW,eGW,EcBSE)
! Compute the Bethe-Salpeter excitation energies
implicit none
include 'parameters.h'
! Input variables
logical,intent(in) :: exchange_kernel
logical,intent(in) :: TDA_W
logical,intent(in) :: TDA
logical,intent(in) :: dBSE
logical,intent(in) :: dTDA
logical,intent(in) :: spin_conserved
logical,intent(in) :: spin_flip
double precision,intent(in) :: eta
integer,intent(in) :: nBas
integer,intent(in) :: nC(nspin)
integer,intent(in) :: nO(nspin)
integer,intent(in) :: nV(nspin)
integer,intent(in) :: nR(nspin)
integer,intent(in) :: nS(nspin)
double precision,intent(in) :: S(nBas,nBas)
double precision,intent(in) :: cW(nBas,nBas,nspin)
double precision,intent(in) :: eW(nBas,nspin)
double precision,intent(in) :: eGW(nBas,nspin)
double precision,intent(in) :: ERI_aaaa(nBas,nBas,nBas,nBas)
double precision,intent(in) :: ERI_aabb(nBas,nBas,nBas,nBas)
double precision,intent(in) :: ERI_bbbb(nBas,nBas,nBas,nBas)
double precision,intent(in) :: dipole_int_aa(nBas,nBas,ncart)
double precision,intent(in) :: dipole_int_bb(nBas,nBas,ncart)
! Local variables
integer :: ispin
integer :: isp_W
logical :: dRPA = .false.
logical :: dRPA_W = .true.
double precision,allocatable :: Aph(:,:)
double precision,allocatable :: Bph(:,:)
double precision,allocatable :: KA(:,:)
double precision,allocatable :: KB(:,:)
double precision :: EcRPA
double precision,allocatable :: OmRPA(:)
double precision,allocatable :: XpY_RPA(:,:)
double precision,allocatable :: XmY_RPA(:,:)
double precision,allocatable :: rho_RPA(:,:,:,:)
integer :: nS_aa,nS_bb,nS_sc
integer :: nS_ab,nS_ba,nS_sf
double precision,allocatable :: OmBSE(:)
double precision,allocatable :: XpY_BSE(:,:)
double precision,allocatable :: XmY_BSE(:,:)
! Output variables
double precision,intent(out) :: EcBSE(nspin)
! Memory allocation
nS_aa = nS(1)
nS_bb = nS(2)
nS_sc = nS_aa + nS_bb
nS_ab = (nO(1) - nC(1))*(nV(2) - nR(2))
nS_ba = (nO(2) - nC(2))*(nV(1) - nR(1))
nS_sf = nS_ab + nS_ba
! TDA
if(TDA) then
write(*,*) 'Tamm-Dancoff approximation activated in phBSE!'
write(*,*)
end if
! Initialization
EcBSE(:) = 0d0
!--------------------------!
! Spin-conserved screening !
!--------------------------!
isp_W = 1
! Compute spin-conserved RPA screening
allocate(Aph(nS_sc,nS_sc),Bph(nS_sc,nS_sc))
allocate(OmRPA(nS_sc),XpY_RPA(nS_sc,nS_sc),XmY_RPA(nS_sc,nS_sc),rho_RPA(nBas,nBas,nS_sc,nspin))
call phULR_A(isp_W,dRPA_W,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,1d0,eW,ERI_aaaa,ERI_aabb,ERI_bbbb,Aph)
if(.not.TDA_W) call phULR_B(isp_W,dRPA_W,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,1d0,ERI_aaaa,ERI_aabb,ERI_bbbb,Bph)
call phULR(TDA_W,nS_aa,nS_bb,nS_sc,Aph,Bph,EcRPA,OmRPA,XpY_RPA,XmY_RPA)
call UGW_excitation_density(nBas,nC,nO,nR,nS_aa,nS_bb,nS_sc,ERI_aaaa,ERI_aabb,ERI_bbbb,XpY_RPA,rho_RPA)
deallocate(Aph,Bph)
!----------------------------!
! Spin-conserved excitations !
!----------------------------!
if(spin_conserved) then
ispin = 1
allocate(Aph(nS_sc,nS_sc),Bph(nS_sc,nS_sc),KA(nS_sc,nS_sc),KB(nS_sc,nS_sc))
allocate(OmBSE(nS_sc),XpY_BSE(nS_sc,nS_sc),XmY_BSE(nS_sc,nS_sc))
! Compute spin-conserved BSE excitation energies
call phULR_A(ispin,dRPA,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,1d0,eGW,ERI_aaaa,ERI_aabb,ERI_bbbb,Aph)
if(.not.TDA) call phULR_B(ispin,dRPA,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,1d0,ERI_aaaa,ERI_aabb,ERI_bbbb,Bph)
call UGW_phBSE_static_kernel_A(ispin,eta,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,nS_sc,1d0,OmRPA,rho_RPA,KA)
if(.not.TDA) call UGW_phBSE_static_kernel_B(ispin,eta,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,nS_sc,1d0,OmRPA,rho_RPA,KB)
Aph(:,:) = Aph(:,:) + KA(:,:)
if(.not.TDA) Bph(:,:) = Bph(:,:) + KB(:,:)
call phULR(TDA,nS_aa,nS_bb,nS_sc,Aph,Bph,EcBSE(ispin),OmBSE,XpY_BSE,XmY_BSE)
call print_excitation_energies('phBSE@GW@UHF','spin-conserved',nS_sc,OmBSE)
call phULR_transition_vectors(ispin,nBas,nC,nO,nV,nR,nS,nS_aa,nS_bb,nS_sc,dipole_int_aa,dipole_int_bb, &
cW,S,OmBSE,XpY_BSE,XmY_BSE)
!-------------------------------------------------
! Compute the dynamical screening at the BSE level
!-------------------------------------------------
if(dBSE) &
call UGW_phBSE_dynamic_perturbation(ispin,dTDA,eta,nBas,nC,nO,nV,nR,nS,nS_aa,nS_bb,nS_sc,nS_sc, &
eW,eGW,ERI_aaaa,ERI_aabb,ERI_bbbb,dipole_int_aa,dipole_int_bb, &
OmRPA,rho_RPA,OmBSE,XpY_BSE,XmY_BSE)
deallocate(Aph,Bph,KA,KB)
deallocate(OmBSE,XpY_BSE,XmY_BSE)
end if
!-----------------------!
! Spin-flip excitations !
!-----------------------!
if(spin_flip) then
ispin = 2
allocate(Aph(nS_sf,nS_sf),Bph(nS_sf,nS_sf),KA(nS_sf,nS_sf),KB(nS_sf,nS_sf))
allocate(OmBSE(nS_sf),XpY_BSE(nS_sf,nS_sf),XmY_BSE(nS_sf,nS_sf))
! Compute spin-conserved BSE excitation energies
call phULR_A(ispin,dRPA,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sf,1d0,eGW,ERI_aaaa,ERI_aabb,ERI_bbbb,Aph)
if(.not.TDA) call phULR_B(ispin,dRPA,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sf,1d0,ERI_aaaa,ERI_aabb,ERI_bbbb,Bph)
call UGW_phBSE_static_kernel_A(ispin,eta,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,nS_sf,1d0,OmRPA,rho_RPA,KA)
if(.not.TDA) call UGW_phBSE_static_kernel_B(ispin,eta,nBas,nC,nO,nV,nR,nS_aa,nS_bb,nS_sc,nS_sf,1d0,OmRPA,rho_RPA,KB)
Aph(:,:) = Aph(:,:) + KA(:,:)
if(.not.TDA) Bph(:,:) = Bph(:,:) + KB(:,:)
call phULR(TDA,nS_aa,nS_bb,nS_sc,Aph,Bph,EcBSE(ispin),OmBSE,XpY_BSE,XmY_BSE)
call print_excitation_energies('phBSE@GW@UHF','spin-flip',nS_sf,OmBSE)
call phULR_transition_vectors(ispin,nBas,nC,nO,nV,nR,nS,nS_ab,nS_ba,nS_sf,dipole_int_aa,dipole_int_bb, &
cW,S,OmBSE,XpY_BSE,XmY_BSE)
!-------------------------------------------------
! Compute the dynamical screening at the BSE level
!-------------------------------------------------
if(dBSE) &
call UGW_phBSE_dynamic_perturbation(ispin,dTDA,eta,nBas,nC,nO,nV,nR,nS,nS_ab,nS_ba,nS_sf,nS_sc, &
eW,eGW,ERI_aaaa,ERI_aabb,ERI_bbbb,dipole_int_aa,dipole_int_bb, &
OmRPA,rho_RPA,OmBSE,XpY_BSE,XmY_BSE)
deallocate(Aph,Bph,KA,KB)
deallocate(OmBSE,XpY_BSE,XmY_BSE)
end if
! Scale properly correlation energy if exchange is included in interaction kernel
if(exchange_kernel) then
EcBSE(:) = 0.5d0*EcBSE(:)
else
EcBSE(2) = 0.0d0
end if
end subroutine