[gmx-users] diffusion constant

[parinald at unsl.edu.ar]

Hello:
      I try to calculate diffusion constant for Na+ (or Cl-) in water with
g_msd.
When I use -mol opcion

          <D> = 0.179 Std. Dev. = 0.000 Error = 0.000
           D[       Na+] 0.179 (+/- 0.283) 1e-5 cm^2/s

If I not use -mol opcion:

           D[       Na+] 0.330 (+/- 1.489) 1e-5 cm^2/s

Which is the correct value?
                           Thank you.Pablo.