anchor.diff:             call dimer_io%position%append(colloids%pos)
              call dimer_io%velocity%append(colloids%vel)
              call dimer_io%image%append(colloids%image)
  +           call omega_el%append(omega(3))
           end if
   
        end do md_loop
  
positive.code:                 xvec=parallel_v)
             call transverse_vacf%add((i-i_release)*N_MD_steps+j-1, correlate_block_dot, &
                  xvec=transverse_v)
             call omega_el%append(omega(3))
          end if
  
          if ((sampling) .and. (modulo(j, colloid_sampling)==0)) then
  
negative.code:        bulk_change, ior(H5MD_LINEAR,H5MD_STORE_TIME), step=N_MD_steps, &
         time=N_MD_steps*dt, offset_by_one=.true.)
    call omega_el%create_time(hfile%observables, 'omega', &
         omega(3), ior(H5MD_LINEAR,H5MD_STORE_TIME), step=colloid_sampling, &
         time=colloid_sampling*dt, offset_by_one=.true.)
  
    if (dimer) then
       colloids% pos(3,:) = solvent_cells% edges(3)/2.d0
  