  We used the von Neumann entropy to study the single and many-particle on-site
localizations of stationary states for an anisotropic Heisenberg spin-1/2
chain. With a constructed bounded sequence of on-site energies for single and
many-particle systems we demonstrate that the von Neumann entropy approaches
zero indicating strong on-site localizations for all states. On the contrary,
random on-site energy sequence does not lead to strong on-site confinement of
all states. Our numerical results indicate that the von Neumann entropy
provides a new insight to analyze on-site localizations for these systems.
