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https://github.com/pfloos/quack
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48 lines
814 B
Fortran
48 lines
814 B
Fortran
subroutine huckel_guess(nBas,S,Hc,X,c)
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! Hickel guess
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implicit none
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! Input variables
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integer,intent(in) :: nBas
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double precision,intent(in) :: S(nBas,nBas)
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double precision,intent(in) :: Hc(nBas,nBas)
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double precision,intent(in) :: X(nBas,nBas)
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! Local variables
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integer :: mu,nu
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double precision :: a
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double precision,allocatable :: F(:,:)
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! Output variables
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double precision,intent(out) :: c(nBas,nBas)
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! Memory allocation
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allocate(F(nBas,nBas))
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! Extended Huckel parameter
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a = 1.75d0
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! GWH approximation
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do mu=1,nBas
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F(mu,mu) = Hc(mu,mu)
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do nu=mu+1,nBas
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F(mu,nu) = 0.5d0*a*S(mu,nu)*(Hc(mu,mu) + Hc(nu,nu))
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F(nu,mu) = F(mu,nu)
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enddo
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enddo
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call core_guess(nBas,F,X,c)
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end subroutine
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