Normal Mode Analysis of a Single Polyethylene Chain

摘要

In certain cases, atomistic simulations of systems with one-dimensional symmetry have shown divergent (infinite) heat conduction properties, even when the interactions are anharmonic. One limitation of many previous works, however, is that toy models were used and thus the resulting conclusions could not be easily extended to more real materials found in nature. In this paper, we examine a more realistic model of a single polyethylene chain, using the AIREBO potential to describe the atomic interactions. We computed normal mode correlation functions and noticed that when the domain is longer than 40 unit cells, the lowest frequency modes in the system remain strongly correlated after five nanoseconds of simulation time. This retention of energy correlation over such a long period identifies these modes as possible sources of anomalous energy transport in a real system. This finding suggests that new and cheap polymeric materials can be engineered to exhibit high thermal conductivity.