To design a process for the assembly or self-assembly of a nanomachine
requires knowing the degree of spatial control needed to put the comp
onents together. A useful starting point in this area of study is the
concept of a docking envelope, which is a continuous region of initial
condition parameter space for which two structures will dock. In this
paper docking envelopes, determined from molecular dynamics simulatio
n, are presented for the assembly of a molecular bearing consisting of
two concentric carbon nanotubes. in-the beginning of each simulation
the outer nanotube (sleeve) is held in place and the inner nanotube (s
haft) starts far away from, but is given an initial velocity toward, t
he sleeve. The docking envelope in this case is delineated by the init
ial offset from a coaxial geometry. In order to address recent concern
s about the effects of zero-point energy leakage and chaos in classica
l simulations of nanomachine components, docking envelopes from two ty
pes of simulations are presented: fully atomistic (all degrees of free
dom included) and rigid body (each nanotube rigid but shaft allowed to
rotate and translate).