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https://github.com/pfloos/quack
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53 lines
1.3 KiB
Fortran
53 lines
1.3 KiB
Fortran
subroutine restricted_elda_correlation_individual_energy(nEns,aLF,nGrid,weight,rhow,rho,Ec)
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! Compute LDA correlation individual energy of 2-glomium for various states
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implicit none
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include 'parameters.h'
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! Input variables
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integer,intent(in) :: nEns
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double precision,intent(in) :: aLF(nEns)
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integer,intent(in) :: nGrid
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double precision,intent(in) :: weight(nGrid)
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double precision,intent(in) :: rhow(nGrid)
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double precision,intent(in) :: rho(nGrid)
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! Local variables
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integer :: iG
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double precision :: r
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double precision :: rI
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double precision :: ec_p,dFcdr
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! Output variables
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double precision,intent(out) :: Ec
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! Compute eLDA correlation potential
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Ec = 0d0
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do iG=1,nGrid
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r = max(0d0,rho(iG))
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rI = max(0d0,rho(iG))
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if(r > threshold .and. rI > threshold) then
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ec_p = aLF(1)/(1d0 + aLF(2)*r**(-1d0/6d0) + aLF(3)*r**(-1d0/3d0))
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dFcdr = aLF(2)*r**(-1d0/6d0) + 2d0*aLF(3)*r**(-1d0/3d0)
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dFcdr = dFcdr/(1d0 + aLF(2)*r**(-1d0/6d0) + aLF(3)*r**(-1d0/3d0))
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dFcdr = ec_p*dFcdr/(6d0*r)
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dFcdr = ec_p + dFcdr*r
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Ec = Ec + weight(iG)*(ec_p*rI + dFcdr*r*rI - dFcdr*r*r)
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end if
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end do
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end subroutine restricted_elda_correlation_individual_energy
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