  In this manuscript we study the confinement of bosonic and spinning test
particles in smooth Randall-Sundrum models. For this, we show that it is
possible to find an effective potential which describe the motion of the
particle over the extra dimension. For the bosonic case it is a known fact that
free test particles cannot be localized neither in thin nor thick branes.
Recently, a coupling to a scalar field has been used to localize a limited
range of masses. Up to now, no mechanism has been found that can trap test
particles of any mass over the brane. To solve this, we show that a coupling
with the dilaton can trap particles of any mass. Next we analyze the spinning
particle. The spin variables $\psi^{P}$ introduces an interaction with the
curvature Riemann tensor. This introduces a correction to the effective
potential. By analyzing it, we find that the spinning particle can be localized
at a position different of the brane. We also show that a spinning particle
over the brane can escape to infinity. Therefore, we can conclude that free
bosonic and spinning particles are not trapped to the brane.
