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https://github.com/pfloos/quack
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86 lines
2.4 KiB
Fortran
86 lines
2.4 KiB
Fortran
subroutine ULYP_gga_correlation_potential(nGrid,weight,nBas,AO,dAO,rho,drho,Fc)
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! Compute LYP correlation potential
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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) :: nGrid
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double precision,intent(in) :: weight(nGrid)
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integer,intent(in) :: nBas
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double precision,intent(in) :: AO(nBas,nGrid)
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double precision,intent(in) :: dAO(ncart,nBas,nGrid)
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double precision,intent(in) :: rho(nGrid,nspin)
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double precision,intent(in) :: drho(ncart,nGrid,nspin)
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! Local variables
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integer :: mu,nu,iG
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double precision :: vAO,gaAO,gbAO
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double precision :: ra,rb,r
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double precision :: ga,gab,gb,g
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double precision :: a,b,c,d
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double precision :: Cf,omega,delta
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! Output variables
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double precision,intent(out) :: Fc(nBas,nBas)
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! Prameter of the functional
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a = 0.04918d0
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b = 0.132d0
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c = 0.2533d0
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d = 0.349d0
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Cf = 3d0/10d0*(3d0*pi**2)**(2d0/3d0)
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! Compute matrix elements in the AO basis
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Fc(:,:) = 0d0
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do mu=1,nBas
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do nu=1,nBas
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do iG=1,nGrid
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ra = max(0d0,rho(iG,1))
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rb = max(0d0,rho(iG,2))
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r = ra + rb
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if(r > threshold) then
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ga = drho(1,iG,1)**2 + drho(2,iG,1)**2 + drho(3,iG,1)**2
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gb = drho(1,iG,2)**2 + drho(2,iG,2)**2 + drho(3,iG,2)**2
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gab = drho(1,iG,1)*drho(1,iG,2) + drho(2,iG,1)*drho(2,iG,2) + drho(3,iG,1)*drho(3,iG,2)
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g = ga + gab + gb
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omega = exp(-c*r**(-1d0/3d0))/(1d0 + d*r**(-1d0/3d0))*r**(-11d0/3d0)
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delta = c*r**(-1d0/3d0) + d*r**(-1d0/3d0)/(1d0 + d*r**(-1d0/3d0))
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vAO = weight(iG)*AO(mu,iG)*AO(nu,iG)
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Fc(mu,nu) = Fc(mu,nu) + vAO
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gaAO = drho(1,iG,1)*(dAO(1,mu,iG)*AO(nu,iG) + AO(mu,iG)*dAO(1,nu,iG)) &
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+ drho(2,iG,1)*(dAO(2,mu,iG)*AO(nu,iG) + AO(mu,iG)*dAO(2,nu,iG)) &
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+ drho(3,iG,1)*(dAO(3,mu,iG)*AO(nu,iG) + AO(mu,iG)*dAO(3,nu,iG))
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gaAO = weight(iG)*gaAO
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gbAO = drho(1,iG,2)*(dAO(1,mu,iG)*AO(nu,iG) + AO(mu,iG)*dAO(1,nu,iG)) &
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+ drho(2,iG,2)*(dAO(2,mu,iG)*AO(nu,iG) + AO(mu,iG)*dAO(2,nu,iG)) &
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+ drho(3,iG,2)*(dAO(3,mu,iG)*AO(nu,iG) + AO(mu,iG)*dAO(3,nu,iG))
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gbAO = weight(iG)*gbAO
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Fc(mu,nu) = Fc(mu,nu) + 2d0*gaAO + gbAO
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end if
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end do
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end do
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end do
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end subroutine ULYP_gga_correlation_potential
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