anchor.diff:                  call find_excitation_permutation2(cdet%f, connection)
   
                   ! 5b. Find the connecting matrix element.
  -                hmatel = slater_condon2_mol(connection%from_orb(1), connection%from_orb(2), &
  -                                            connection%to_orb(1), connection%to_orb(2), connection%perm)
  +                hmatel = slater_condon2_mol_excit(connection%from_orb(1), connection%from_orb(2), &
  +                                                  connection%to_orb(1), connection%to_orb(2), connection%perm)
               else
                   ! Carelessly selected ij with no possible excitations.  Such
                   ! events are not worth the cost of renormalising the generation
  
positive.code:         use excitations, only: excit
          use fciqmc_data, only: pattempt_single
          use excitations, only: find_excitation_permutation1, find_excitation_permutation2
          use hamiltonian_molecular, only: slater_condon1_mol, slater_condon2_mol
  
          use dSFMT_interface, only: genrand_real2
  
  
negative.code:                 call find_excitation_permutation2(cdet%f, connection)
  
                  ! 5b. Find the connecting matrix element.
                  hmatel = slater_condon2_mol_excit(connection%from_orb(1), connection%from_orb(2), &
                                                    connection%to_orb(1), connection%to_orb(2), connection%perm)
              else
                  ! Forbidden---connection%to_orb(2) is already occupied.
                  hmatel = 0.0_p
  