Dear all,<br><br>I'm trying to compare the diffusion constants
resulting from g_msd -mol and g_velacc -mol -nonormalize. The agreement
for pure water (512 molecules, 300 K) seems fine (g_analyze output of
g_velacc falls into the +- interval of g_msd), but for a more complex
system (4000 waters + 80 small solutes, 290 K), the resulting velocity
ACF decays to a nonzero value. This might result from COM motion, but I
think I'm removing it:<br>
<br>; mode for center of mass motion removal<br>comm-mode = Linear<br>; number of steps for center of mass motion removal<br>nstcomm = 1<br><br>Any hints on what this might mean?<br><br>
Best regards,<br><font color="#888888">Vasilii</font>