Carbon nanotube oscillators encapsulating a platinum nanocluster: A molecular dynamics study

Molecular dynamics simulations are performed to study carbon nanotube (CNT) oscillators that encapsulate an oscillating platinum nanocluster. Our calculations show that the nanocluster has a nearly constant motion except at the two ends of CNT, where the nanocluster is accelerated due to the potential gradient between its parts that are outside and inside the CNT. The oscillation frequency ω is found to increase with the temperature below 400 K and almost does not vary between 400 and 800 K. The calculated Lindemann index and radial distribution indicate that the platinum cluster starts to melt at 800 K and hence ω decreases and fluctuates considerably with the temperatures higher than 800 K. The relation between ω and the number of atoms n in platinum cluster is also studied. It is found that ω first decreases with n. When n exceeds a threshold value, the part of nanocluster running beyond the ends of CNT is deformed evidently, leading to fluctuations of ω with n.