Hi Dear Gmx Users, Do not just following procedure can be usedby gen_vel: NVT gen_vel = yes gen_temp=300 gen_seed=-1 NPT gen_vel=no MD gen_vel=no i want to study the changing of velocity in md stage. Can I use the following method: NVT gen_vel = yes gen_temp=298 gen_seed=-1 NPT gen_vel=no MD gen_vel = yes gen_temp=298 gen_seed=-1