molecular velocity profile

Hi Dear users
I am trying to obtain molecular velocity profile and COM velocity profile across the channel for a system consisting water and some other atoms, how can I do it?
Is it enough to use ave/spatial command or I must use compute commands or something else?
It is important for me to obtain the velocity of water molecules, not hydrogen and oxygen atoms because of molecular rotational movements.
Thanks alot
Nich Nack

There are a few compute */molecule commands, like com
and msd. But they won't work in conjunction with fix
ave/spatial to get a profile. I suppose it would be
possible to let fix ave/spatial take a list of molecule
properties, like COM velocity as an input.

But I think for now you'd have to post-process this.

Also, if you have reasonable statistics, I don't imagine
that a per-atom profile on O,H will be any different
than a molecular one.