From 3b63d807fcff110efac2bb1b4c8754322bf75c67 Mon Sep 17 00:00:00 2001
From: Kevin Gasperich <kgasperich@gmail.com>
Date: Fri, 24 Jan 2020 07:57:38 -0600
Subject: [PATCH] added complex huckel

---
 src/scf_utils/huckel_complex.irp.f | 42 ++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 src/scf_utils/huckel_complex.irp.f

diff --git a/src/scf_utils/huckel_complex.irp.f b/src/scf_utils/huckel_complex.irp.f
new file mode 100644
index 00000000..3fa1b4b0
--- /dev/null
+++ b/src/scf_utils/huckel_complex.irp.f
@@ -0,0 +1,42 @@
+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
+  complex*16, 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_complex(i,j) * (ao_one_e_integrals_diag(i) + ao_one_e_integrals_diag(j))
+    enddo
+    A(j,j) = ao_one_e_integrals_diag(j) + dble(ao_two_e_integral_alpha_complex(j,j))
+    if (dabs(dimag(ao_two_e_integral_alpha_complex)) .gt. 1.0d-10) then
+      stop 'diagonal elements of ao_bi_elec_integral_alpha should be real'
+    endif
+  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)
+  call zlacp2('X', ao_num, ao_num, A, size(A,1), &
+         Fock_matrix_ao_alpha_complex, size(Fock_matrix_ao_alpha_complex,1))
+  call zlacp2('X', ao_num, ao_num, A, size(A,1), &
+         Fock_matrix_ao_beta_complex,  size(Fock_matrix_ao_beta_complex, 1))
+  
+
+!  TOUCH mo_coef
+
+  TOUCH Fock_matrix_ao_alpha_complex Fock_matrix_ao_beta_complex
+  mo_coef_complex = eigenvectors_fock_matrix_mo_complex
+  SOFT_TOUCH mo_coef_complex
+  call save_mos
+  deallocate(A)
+
+end