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qp2/src/scf_utils/huckel.irp.f

36 lines
1004 B
Fortran

subroutine huckel_guess
implicit none
BEGIN_DOC
! Build the MOs using the extended Huckel model
END_DOC
integer :: i,j
double precision :: accu
double precision :: c
character*(64) :: label
double precision, allocatable :: A(:,:)
label = "Guess"
c = 0.5d0 * 1.75d0
allocate (A(ao_num, ao_num))
A = 0.d0
do j=1,ao_num
do i=1,ao_num
A(i,j) = c * ao_overlap(i,j) * &
(ao_one_e_integrals_diag(i) + ao_one_e_integrals_diag(j) )
enddo
A(j,j) = ao_one_e_integrals_diag(j) + ao_two_e_integral_alpha(j,j)
enddo
Fock_matrix_ao_alpha(1:ao_num,1:ao_num) = A(1:ao_num,1:ao_num)
Fock_matrix_ao_beta (1:ao_num,1:ao_num) = A(1:ao_num,1:ao_num)
TOUCH Fock_matrix_ao_alpha Fock_matrix_ao_beta
mo_coef = eigenvectors_fock_matrix_mo
call restore_symmetry(ao_num,mo_num,mo_coef,size(mo_coef,1),1.d-10)
call orthonormalize_mos
SOFT_TOUCH mo_coef
call save_mos
deallocate(A)
end