Volume fraction is the fraction of the region volume that you are filling
with particles, where each particle occupies some volume based
on its interaction length (e.g. cutoff, or "near" parameter in the
fix deposit command). If fix deposit was unsuccessful inserting
as many particles as you asked for, it means it tried up to Q times
and couldn't find a valid location to insert it.
2011/4/2 XiaoJing <[email protected]>: