anchor.diff:  
           case(2)
   
  +            ! < D | H | D_{ij}^{ab} > = < ij || ab >
  +
               ! Two electron operator
               hmatel = get_two_e_int(excitation%from_orb(1), excitation%from_orb(2), excitation%to_orb(1), excitation%to_orb(2))
   
  
positive.code:         hmatel = 0.0_dp
  
          select case(excitation%nexcit)
          case(0)
  
              root_det = decode_det(root_det_f)
  
              ! One electron operator
              do i = 1, nel
  
negative.code: 
              root_det = decode_det(root_det_f)
  
              ! < D | H | D_i^a > = < i | h(a) | a > + \sum_j < ij || aj >
  
              ! One electron operator
              hmatel = hmatel + get_one_e_int(excitation%from_orb(1), excitation%to_orb(1)) 
  
  