MSD calculation for lithium ions

Hello,

I am uncertain why when I do a msd calculation with gromacs I am obtaining the following strange results: I would appreciate a lot if someone could help me out please. Thank you! For example, the command I am using is gmx msd -f t550_prodrun.xtc -s t550_prodrun.tpr -o msd-Li.xvg

Dear @mdiazseg , please give us more details about the system and simulation you are running. What exactly is your issue?