A Model Platform for Rapid, Robust, Directed, and Long-Range Vibrational Energy Transport: Insights from a Mixed Quantum-Classical Study of a 1D Molecular Chain

The design of devices that efficiently and robustly transport vibrational energy is of importance to applications in molecular electronics and quantum information processing. In this work, we study a 1D model of a molecular chain with repeating carbonyl-containing subunits that exhibits extremely rapid vibrational energy transport between its distal subunits. This model contains two key features: (i) the bare frequencies of the two distal carbonyl groups are equally shifted with respect to those of the remaining groups, and (ii) the carbonyl groups are coupled to a bath of coupled low-frequency harmonic oscillators. Using mixed quantum-classical dynamics, we investigate the effects of bath temperature and chain length on the energy transfer along the chain, following an excitation of a carbonyl mode at one end of the chain. At very low temperatures, we find that no substantial energy transfer takes place; however, over a wide range of higher temperatures, the excitation energy rapidly hops between the two terminal carbonyl groups regardless of the chain length. These findings suggest that such a model could be used as a platform for building devices that are capable of rapid, robust, directed, and long-range vibrational energy transport.