anchor.diff:              ! 1.1 Generate first random excitation and probability of spawning there from cdet 
               !    (in this case we stay on the same place)
               Pgen_ki = 1
  -            hmatel_ki =  sc0_ptr(cdet%f) - fold_line !***optimise this with stored/calculated values
  +            hmatel_ki =  sc0_ptr(cdet%f) - H00 - fold_line !***optimise this with stored/calculated values
               
   
               ! 1.2 Generate the second random excitation 
  
positive.code:         !        and the child determinant, on which progeny are spawned.
          use determinants, only: det_info
          use excitations, only: excit
          use fciqmc_data, only: tau
          use excitations, only: create_excited_det_complete
  
          type(det_info), intent(in) :: cdet
  
negative.code:         ! Note that population and tot_population refer to a single 'type' of
          ! population, i.e. either a set of Hamiltonian walkers or a set of
          ! Hellmann--Feynman walkers.
          !      ___
          !     / _ \
          !    | / \ |
          !     \\.//
  
  
  
          use death, only: stochastic_death
  