mirror of
https://github.com/pfloos/quack
synced 2024-06-25 22:52:18 +02:00
62 lines
1.5 KiB
Fortran
62 lines
1.5 KiB
Fortran
subroutine huckel_guess(nBas,nO,S,Hc,ERI,J,K,X,cp,Fp,e,c,P)
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! Hickel guess of the molecular orbitals for HF calculation
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implicit none
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! Input variables
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integer,intent(in) :: nBas
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integer,intent(in) :: nO
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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) :: ERI(nBas,nBas,nBas,nBas)
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double precision,intent(inout):: J(nBas,nBas)
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double precision,intent(inout):: K(nBas,nBas)
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double precision,intent(in) :: X(nBas,nBas)
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double precision,intent(inout):: cp(nBas,nBas)
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double precision,intent(inout):: Fp(nBas,nBas)
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double precision,intent(inout):: e(nBas)
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double precision,intent(inout):: P(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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! Output variables
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double precision,intent(out) :: c(nBas,nBas)
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a = 1.75d0
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Fp = matmul(transpose(X),matmul(Hc,X))
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cp(:,:) = Fp(:,:)
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call diagonalize_matrix(nBas,cp,e)
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c = matmul(X,cp)
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P(:,:) = 2d0*matmul(c(:,1:nO),transpose(c(:,1:nO)))
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call Coulomb_matrix_AO_basis(nBas,P,ERI,J)
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call exchange_matrix_AO_basis(nBas,P,ERI,K)
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do mu=1,nBas
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Fp(mu,mu) = Hc(mu,mu) + J(mu,mu) + 0.5d0*K(mu,mu)
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do nu=mu+1,nBas
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Fp(mu,nu) = 0.5d0*a*S(mu,nu)*(Hc(mu,mu) + Hc(nu,nu))
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Fp(nu,mu) = Fp(mu,nu)
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enddo
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enddo
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Fp = matmul(transpose(X),matmul(Fp,X))
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cp(:,:) = Fp(:,:)
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call diagonalize_matrix(nBas,cp,e)
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c = matmul(X,cp)
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end subroutine
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