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QuAcK/src/eDFT/unrestricted_hybrid_exchange_energy.f90

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2021-02-14 22:52:17 +01:00
subroutine unrestricted_hybrid_exchange_energy(DFA,LDA_centered,nEns,wEns,aCC_w1,aCC_w2,nGrid,weight,nBas,P,FxHF, &
rho,drho,Ex,Cx_choice)
! Compute the exchange energy for hybrid functionals
implicit none
include 'parameters.h'
! Input variables
character(len=12),intent(in) :: DFA
logical,intent(in) :: LDA_centered
integer,intent(in) :: nEns
double precision,intent(in) :: wEns(nEns)
double precision,intent(in) :: aCC_w1(3)
double precision,intent(in) :: aCC_w2(3)
integer,intent(in) :: nGrid
double precision,intent(in) :: weight(nGrid)
integer,intent(in) :: nBas
double precision,intent(in) :: P(nBas,nBas)
double precision,intent(in) :: FxHF(nBas,nBas)
double precision,intent(in) :: rho(nGrid)
double precision,intent(in) :: drho(ncart,nGrid)
integer,intent(in) :: Cx_choice
! Local variables
double precision :: ExLDA,ExGGA,ExHF
double precision :: a0,aX
! Output variables
double precision,intent(out) :: Ex
select case (DFA)
case ('HF')
call unrestricted_fock_exchange_energy(nBas,P,FxHF,Ex)
case ('B3')
a0 = 0.20d0
aX = 0.72d0
call unrestricted_lda_exchange_energy('S51 ',LDA_centered,nEns,wEns,aCC_w1,aCC_w2,nGrid,weight,&
rho,ExLDA,Cx_choice)
call unrestricted_gga_exchange_energy('B88 ',nEns,wEns,nGrid,weight,rho,drho,ExGGA)
call unrestricted_fock_exchange_energy(nBas,P,FxHF,ExHF)
Ex = ExLDA &
+ a0*(ExHF - ExLDA) &
+ aX*(ExGGA - ExLDA)
case ('PBE')
call unrestricted_gga_exchange_energy('PBE ',nEns,wEns,nGrid,weight,rho,drho,ExGGA)
call unrestricted_fock_exchange_energy(nBas,P,FxHF,ExHF)
Ex = 0.25d0*ExHF + 0.75d0*ExGGA
case default
call print_warning('!!! Hybrid exchange energy not available !!!')
stop
end select
end subroutine unrestricted_hybrid_exchange_energy