[gmx-users] autocorrelation function

[Jozef Hritz]

	 Gromacs Users,

I would like to ask one technical question, how to calculate velocity
autocorrelation funcion for center of mass of polymer for describing
global translation motion of polymer.

I know that g_velacc is able to calculate velocity autocorrelation funcion
for set of atoms defined in index file. Thus I can choose atoms of
polymers and the resulting function is average of contribution comming
from all atoms. However, this result contains also other contributions
(rotation, ...) not only translation motion of polymer.

Thank You very much for help

Jozef