  In recent years, experimental techniques have enabled the creation of
endofullerene peapod nanomolecular assemblies. It was previously suggested that
the rotor model resulting from the placement of dipolar linear rotors in
one-dimensional lattices at low temperature has a transition between ordered
and disordered phases. We use the density matrix renormalization group (DMRG)
to compute ground states of chains of up to 50 rotors and provide further
evidence of the phase transition in the form of a diverging entanglement
entropy. We also propose two methods and present some first steps towards
rotational spectra of such nanomolecular assemblies using DMRG. The present
work showcases the power of DMRG in this new context of interacting molecular
rotors and opens the door to the study of fundamental questions regarding
criticality in systems with continuous degrees of freedom.
