anchor.diff:       if (i .gt. 2000) then
           fixed = .false.
        end if
  +     if (modulo(i,100)==0) then
  +        call concentration_field
  +        write(18,*) conc_z, colloid_pos
  +     end if
     end do setup
   
     call thermo_data%append(hfile, temperature, e1+e2+e_wall, kin_e, e1+e2+e_wall+kin_e, add=.false., force=.true.)
  
positive.code: 
    open(17,file ='dimerdata_FullExp_1.txt')
    open(19,file ='dimerdata_vx_flow_wall.txt')  
  
    colloids% species(1) = 1
    colloids% species(2) = 2
    colloids% vel = 0
  
negative.code:   sigma_C = PTread_d(config, 'sigma_C')
    sigma_N = PTread_d(config, 'sigma_N')
  
    epsilon(:,1) = PTread_dvec(config, 'epsilon_C', 3)
    epsilon(:,2) = PTread_dvec(config, 'epsilon_N', 3)
  
    sigma(:,1) = sigma_C
    sigma(:,2) = sigma_N
  